diff --git a/include/linkdefs.h b/include/linkdefs.h
index 6aefbbca..38e8090b 100644
--- a/include/linkdefs.h
+++ b/include/linkdefs.h
@@ -13,8 +13,8 @@
 #include <stdint.h>
 
 #define RGBDS_OBJECT_VERSION_STRING "RGB%1hhu"
-#define RGBDS_OBJECT_VERSION_NUMBER (uint8_t)9
-#define RGBDS_OBJECT_REV 4
+#define RGBDS_OBJECT_VERSION_NUMBER 9
+#define RGBDS_OBJECT_REV 4U
 
 enum AssertionType {
 	ASSERT_WARN,
diff --git a/src/asm/asmy.y b/src/asm/asmy.y
index 015bf4c5..0452d79f 100644
--- a/src/asm/asmy.y
+++ b/src/asm/asmy.y
@@ -9,6 +9,7 @@
 %{
 #include <ctype.h>
 #include <errno.h>
+#include <inttypes.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -79,7 +80,7 @@ size_t symvaluetostring(char *dest, size_t maxLength, char *symName,
 			strncpy(dest, write_ptr, maxLength + 1);
 		} else {
 			fullLength = snprintf(dest, maxLength + 1,
-							  mode ? mode : "$%X",
+							  mode ? mode : "$%" PRIX32,
 						      value);
 		}
 
diff --git a/src/asm/fstack.c b/src/asm/fstack.c
index 3ebfe51c..ca8e675c 100644
--- a/src/asm/fstack.c
+++ b/src/asm/fstack.c
@@ -10,14 +10,15 @@
  * FileStack routines
  */
 
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <errno.h>
+#include <inttypes.h>
 #include <limits.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 #include <unistd.h>
 
 #include "asm/fstack.h"
@@ -69,7 +70,7 @@ static void pushcontext(void)
 	struct sContext **ppFileStack;
 
 	if (++nFileStackDepth > nMaxRecursionDepth)
-		fatalerror("Recursion limit (%d) exceeded", nMaxRecursionDepth);
+		fatalerror("Recursion limit (%u) exceeded", nMaxRecursionDepth);
 
 	ppFileStack = &pFileStack;
 	while (*ppFileStack)
@@ -271,12 +272,12 @@ void fstk_Dump(void)
 	pLastFile = pFileStack;
 
 	while (pLastFile) {
-		fprintf(stderr, "%s(%d) -> ", pLastFile->tzFileName,
+		fprintf(stderr, "%s(%" PRId32 ") -> ", pLastFile->tzFileName,
 			pLastFile->nLine);
 		pLastFile = pLastFile->pNext;
 	}
 
-	fprintf(stderr, "%s(%d)", tzCurrentFileName, nLineNo);
+	fprintf(stderr, "%s(%" PRId32 ")", tzCurrentFileName, nLineNo);
 }
 
 void fstk_DumpToStr(char *buf, size_t buflen)
@@ -286,7 +287,7 @@ void fstk_DumpToStr(char *buf, size_t buflen)
 	size_t len = buflen;
 
 	while (pLastFile) {
-		retcode = snprintf(&buf[buflen - len], len, "%s(%d) -> ",
+		retcode = snprintf(&buf[buflen - len], len, "%s(%" PRId32 ") -> ",
 				   pLastFile->tzFileName, pLastFile->nLine);
 		if (retcode < 0)
 			fatalerror("Failed to dump file stack to string: %s",
@@ -298,8 +299,8 @@ void fstk_DumpToStr(char *buf, size_t buflen)
 		pLastFile = pLastFile->pNext;
 	}
 
-	retcode = snprintf(&buf[buflen - len], len, "%s(%d)", tzCurrentFileName,
-			   nLineNo);
+	retcode = snprintf(&buf[buflen - len], len, "%s(%" PRId32 ")",
+			   tzCurrentFileName, nLineNo);
 	if (retcode < 0)
 		fatalerror("Failed to dump file stack to string: %s",
 			   strerror(errno));
diff --git a/src/asm/lexer.c b/src/asm/lexer.c
index e77bcb41..d4ef3a38 100644
--- a/src/asm/lexer.c
+++ b/src/asm/lexer.c
@@ -7,12 +7,13 @@
  */
 
 #include <assert.h>
+#include <ctype.h>
+#include <inttypes.h>
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 #include <strings.h>
-#include <ctype.h>
 
 #include "asm/asm.h"
 #include "asm/fstack.h"
@@ -120,7 +121,7 @@ void yyunputstr(const char *s)
 void lex_BeginStringExpansion(const char *tzName)
 {
 	if (++nNbStringExpansions > nMaxRecursionDepth)
-		fatalerror("Recursion limit (%d) exceeded", nMaxRecursionDepth);
+		fatalerror("Recursion limit (%u) exceeded", nMaxRecursionDepth);
 
 	struct sStringExpansionPos *pNewStringExpansion =
 		malloc(sizeof(*pNewStringExpansion));
@@ -371,7 +372,7 @@ uint32_t lex_FloatAlloc(const struct sLexFloat *token)
 bool lex_CheckCharacterRange(uint16_t start, uint16_t end)
 {
 	if (start > end || start < 1 || end > 127) {
-		yyerror("Invalid character range (start: %u, end: %u)",
+		yyerror("Invalid character range (start: %" PRIu16 ", end: %" PRIu16 ")",
 			start, end);
 		return false;
 	}
@@ -672,7 +673,7 @@ size_t yylex_ReadBracketedSymbol(char *dest, size_t index)
 			 * so it's handled differently
 			 */
 			static const char * const formatSpecifiers[] = {
-				"", "%x", "%X", "%d"
+				"", "%" PRIx32, "%" PRIX32, "%" PRId32
 			};
 			/* Prevent reading out of bounds! */
 			const char *designatedMode;
diff --git a/src/asm/macro.c b/src/asm/macro.c
index 72de2091..6e8ecf42 100644
--- a/src/asm/macro.c
+++ b/src/asm/macro.c
@@ -1,5 +1,6 @@
 
 #include <assert.h>
+#include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -82,7 +83,7 @@ void macro_SetUniqueID(uint32_t id)
 		uniqueIDPtr = NULL;
 	} else {
 		/* The buffer is guaranteed to be the correct size */
-		sprintf(uniqueIDBuf, "_%u", id);
+		sprintf(uniqueIDBuf, "_%" PRIu32, id);
 		uniqueIDPtr = uniqueIDBuf;
 	}
 }
diff --git a/src/asm/main.c b/src/asm/main.c
index 157b6aa2..a90bc075 100644
--- a/src/asm/main.c
+++ b/src/asm/main.c
@@ -167,7 +167,7 @@ void opt_Parse(char *s)
 		/* fallthrough */
 	case 'p':
 		if (strlen(&s[1]) <= 2) {
-			int32_t result;
+			int result;
 			unsigned int fillchar;
 
 			result = sscanf(&s[1], "%x", &fillchar);
@@ -551,10 +551,11 @@ int main(int argc, char *argv[])
 		fclose(dependfile);
 
 	if (nIFDepth != 0)
-		errx(1, "Unterminated IF construct (%u levels)!", nIFDepth);
+		errx(1, "Unterminated IF construct (%" PRIu32 " levels)!",
+		     nIFDepth);
 
 	if (nUnionDepth != 0) {
-		errx(1, "Unterminated UNION construct (%u levels)!",
+		errx(1, "Unterminated UNION construct (%" PRIu32 " levels)!",
 		     nUnionDepth);
 	}
 
@@ -564,8 +565,9 @@ int main(int argc, char *argv[])
 	timespent = ((double)(nEndClock - nStartClock))
 		     / (double)CLOCKS_PER_SEC;
 	if (verbose) {
-		printf("Success! %u lines in %d.%02d seconds ", nTotalLines,
-		       (int)timespent, ((int)(timespent * 100.0)) % 100);
+		printf("Success! %" PRIu32 " lines in %d.%02d seconds ",
+		       nTotalLines, (int)timespent,
+		       ((int)(timespent * 100.0)) % 100);
 		if (timespent < FLT_MIN_EXP)
 			printf("(INFINITY lines/minute)\n");
 		else
diff --git a/src/asm/math.c b/src/asm/math.c
index 49cd9a33..9f827e24 100644
--- a/src/asm/math.c
+++ b/src/asm/math.c
@@ -10,6 +10,7 @@
  * Fixedpoint math routines
  */
 
+#include <inttypes.h>
 #include <math.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -37,12 +38,16 @@ void math_DefinePI(void)
  */
 void math_Print(int32_t i)
 {
-	if (i >= 0)
-		printf("%d.%05d", i >> 16,
-		       ((int32_t)(fx2double(i) * 100000 + 0.5)) % 100000);
-	else
-		printf("-%d.%05d", (-i) >> 16,
-		       ((int32_t)(fx2double(-i) * 100000 + 0.5)) % 100000);
+	uint32_t u = i;
+	const char *sign = "";
+
+	if (i < 0) {
+		u = -u;
+		sign = "-";
+	}
+
+	printf("%s%" PRIu32 ".%05" PRIu32, sign, u >> 16,
+	       ((uint32_t)(fx2double(u) * 100000 + 0.5)) % 100000);
 }
 
 /*
diff --git a/src/asm/rpn.c b/src/asm/rpn.c
index 31094e17..e75958b0 100644
--- a/src/asm/rpn.c
+++ b/src/asm/rpn.c
@@ -12,6 +12,7 @@
 
 #include <assert.h>
 #include <errno.h>
+#include <inttypes.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
@@ -50,8 +51,8 @@ static uint8_t *reserveSpace(struct Expression *expr, uint32_t size)
 			 * To avoid generating humongous object files, cap the
 			 * size of RPN expressions
 			 */
-			fatalerror("RPN expression cannot grow larger than %d bytes",
-				   MAXRPNLEN);
+			fatalerror("RPN expression cannot grow larger than %lu bytes",
+				   (unsigned long)MAXRPNLEN);
 		else if (expr->nRPNCapacity > MAXRPNLEN / 2)
 			expr->nRPNCapacity = MAXRPNLEN;
 		else
@@ -222,7 +223,8 @@ void rpn_CheckHRAM(struct Expression *expr, const struct Expression *src)
 		/* That range is valid, but only keep the lower byte */
 		expr->nVal &= 0xFF;
 	} else if (expr->nVal < 0 || expr->nVal > 0xFF) {
-		yyerror("Source address $%x not in $FF00 to $FFFF", expr->nVal);
+		yyerror("Source address $%" PRIx32 " not between $FF00 to $FFFF",
+			expr->nVal);
 	}
 }
 
@@ -233,7 +235,8 @@ void rpn_CheckRST(struct Expression *expr, const struct Expression *src)
 	if (rpn_isKnown(expr)) {
 		/* A valid RST address must be masked with 0x38 */
 		if (expr->nVal & ~0x38)
-			yyerror("Invalid address $%x for RST", expr->nVal);
+			yyerror("Invalid address $%" PRIx32 " for RST",
+				expr->nVal);
 		/* The target is in the "0x38" bits, all other bits are set */
 		expr->nVal |= 0xC7;
 	} else {
@@ -260,7 +263,7 @@ static int32_t shift(int32_t shiftee, int32_t amount)
 	if (amount >= 0) {
 		// Left shift
 		if (amount >= 32) {
-			warning(WARNING_SHIFT_AMOUNT, "Shifting left by large amount %d",
+			warning(WARNING_SHIFT_AMOUNT, "Shifting left by large amount %" PRId32,
 				amount);
 			return 0;
 
@@ -276,7 +279,7 @@ static int32_t shift(int32_t shiftee, int32_t amount)
 		// Right shift
 		amount = -amount;
 		if (amount >= 32) {
-			warning(WARNING_SHIFT_AMOUNT, "Shifting right by large amount %d",
+			warning(WARNING_SHIFT_AMOUNT, "Shifting right by large amount %" PRId32,
 				amount);
 			return shiftee < 0 ? -1 : 0;
 
@@ -289,7 +292,7 @@ static int32_t shift(int32_t shiftee, int32_t amount)
 			 * undefined, so use a left shift manually sign-extended
 			 */
 			return (uint32_t)shiftee >> amount
-				| -((uint32_t)1 << (32 - amount));
+				| -(UINT32_C(1) << (32 - amount));
 		}
 	}
 }
@@ -370,18 +373,18 @@ void rpn_BinaryOp(enum RPNCommand op, struct Expression *expr,
 			break;
 		case RPN_SHL:
 			if (src2->nVal < 0)
-				warning(WARNING_SHIFT_AMOUNT, "Shifting left by negative amount %d",
+				warning(WARNING_SHIFT_AMOUNT, "Shifting left by negative amount %" PRId32,
 					src2->nVal);
 
 			expr->nVal = shift(src1->nVal, src2->nVal);
 			break;
 		case RPN_SHR:
 			if (src1->nVal < 0)
-				warning(WARNING_SHIFT, "Shifting negative value %d",
+				warning(WARNING_SHIFT, "Shifting negative value %" PRId32,
 					src1->nVal);
 
 			if (src2->nVal < 0)
-				warning(WARNING_SHIFT_AMOUNT, "Shifting right by negative amount %d",
+				warning(WARNING_SHIFT_AMOUNT, "Shifting right by negative amount %" PRId32,
 					src2->nVal);
 
 			expr->nVal = shift(src1->nVal, -src2->nVal);
@@ -421,7 +424,7 @@ void rpn_BinaryOp(enum RPNCommand op, struct Expression *expr,
 		case RPN_RST:
 		case RPN_CONST:
 		case RPN_SYM:
-			fatalerror("%d is no binary operator", op);
+			fatalerror("%d is not a binary operator", op);
 		}
 
 	} else if (op == RPN_SUB && isDiffConstant(src1, src2)) {
diff --git a/src/asm/section.c b/src/asm/section.c
index 52968fc2..784bb5a8 100644
--- a/src/asm/section.c
+++ b/src/asm/section.c
@@ -1,9 +1,10 @@
 
 #include <errno.h>
+#include <inttypes.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <stdbool.h>
 
 #include "asm/fstack.h"
 #include "asm/main.h"
@@ -64,7 +65,7 @@ static void reserveSpace(uint32_t delta_size)
 	 * A check at the linking stage is still necessary.
 	 */
 	if (newSize > maxSize)
-		fatalerror("Section '%s' is too big (max size = 0x%X bytes, reached 0x%X).",
+		fatalerror("Section '%s' is too big (max size = 0x%" PRIX32 " bytes, reached 0x%" PRIX32 ").",
 			   pCurrentSection->pzName, maxSize, newSize);
 }
 
@@ -100,14 +101,14 @@ static struct Section *getSection(char const *pzName, enum SectionType type,
 			yyerror("BANK only allowed for ROMX, WRAMX, SRAM, or VRAM sections");
 		else if (bank < bankranges[type][0]
 		      || bank > bankranges[type][1])
-			yyerror("%s bank value $%x out of range ($%x to $%x)",
+			yyerror("%s bank value $%" PRIx32 " out of range ($%" PRIx32 " to $%" PRIx32 ")",
 				typeNames[type], bank,
 				bankranges[type][0], bankranges[type][1]);
 	}
 
 	if (alignOffset >= 1 << alignment) {
-		yyerror("Alignment offset must not be greater than alignment (%u < %u)",
-			alignOffset, 1 << alignment);
+		yyerror("Alignment offset must not be greater than alignment (%" PRIu16 " < %u)",
+			alignOffset, 1U << alignment);
 		alignOffset = 0;
 	}
 
@@ -128,7 +129,7 @@ static struct Section *getSection(char const *pzName, enum SectionType type,
 
 	if (org != -1) {
 		if (org < startaddr[type] || org > endaddr(type))
-			yyerror("Section \"%s\"'s fixed address %#x is outside of range [%#x; %#x]",
+			yyerror("Section \"%s\"'s fixed address %#" PRIx32 " is outside of range [%#" PRIx16 "; %#" PRIx16 "]",
 				pzName, org, startaddr[type], endaddr(type));
 	}
 
@@ -167,13 +168,13 @@ static struct Section *getSection(char const *pzName, enum SectionType type,
 			if (org != -1) {
 				/* If both are fixed, they must be the same */
 				if (pSect->nOrg != -1 && pSect->nOrg != org)
-					fail("Section \"%s\" already declared as fixed at different address $%x",
+					fail("Section \"%s\" already declared as fixed at different address $%" PRIx32,
 					     pSect->pzName, pSect->nOrg);
 				else if (pSect->nAlign != 0
 				      && (mask(pSect->nAlign)
 						& (org - pSect->alignOfs)))
-					fail("Section \"%s\" already declared as aligned to %u bytes (offset %u)",
-					     pSect->pzName, 1 << pSect->nAlign,
+					fail("Section \"%s\" already declared as aligned to %u bytes (offset %" PRIu16 ")",
+					     pSect->pzName, 1U << pSect->nAlign,
 					     pSect->alignOfs);
 				else
 					/* Otherwise, just override */
@@ -183,14 +184,14 @@ static struct Section *getSection(char const *pzName, enum SectionType type,
 				if (pSect->nOrg != -1) {
 					if ((pSect->nOrg - alignOffset)
 							& mask(alignment))
-						fail("Section \"%s\" already declared as fixed at incompatible address $%x",
+						fail("Section \"%s\" already declared as fixed at incompatible address $%" PRIx32,
 						     pSect->pzName,
 						     pSect->nOrg);
 				/* Check if alignment offsets are compatible */
 				} else if ((alignOffset & mask(pSect->nAlign))
 					!= (pSect->alignOfs
 							& mask(alignment))) {
-					fail("Section \"%s\" already declared with incompatible %u-byte alignment (offset %u)",
+					fail("Section \"%s\" already declared with incompatible %" PRIu8 "-byte alignment (offset %" PRIu16 ")",
 					     pSect->pzName, pSect->nAlign,
 					     pSect->alignOfs);
 				} else if (alignment > pSect->nAlign) {
@@ -207,7 +208,7 @@ static struct Section *getSection(char const *pzName, enum SectionType type,
 				pSect->nBank = bank;
 			/* If both specify a bank, it must be the same one */
 			else if (bank != -1 && pSect->nBank != bank)
-				fail("Section \"%s\" already declared with different bank %u",
+				fail("Section \"%s\" already declared with different bank %" PRIu32,
 				     pSect->pzName, pSect->nBank);
 		} else {
 			if (pSect->isUnion)
@@ -218,7 +219,7 @@ static struct Section *getSection(char const *pzName, enum SectionType type,
 					fail("Section \"%s\" already declared as floating",
 					     pSect->pzName);
 				else
-					fail("Section \"%s\" already declared as fixed at $%x",
+					fail("Section \"%s\" already declared as fixed at $%" PRIx32,
 					     pSect->pzName, pSect->nOrg);
 			}
 			if (bank != pSect->nBank) {
@@ -226,7 +227,7 @@ static struct Section *getSection(char const *pzName, enum SectionType type,
 					fail("Section \"%s\" already declared as floating bank",
 					     pSect->pzName);
 				else
-					fail("Section \"%s\" already declared as fixed at bank %u",
+					fail("Section \"%s\" already declared as fixed at bank %" PRIu32,
 					     pSect->pzName, pSect->nBank);
 			}
 			if (alignment != pSect->nAlign) {
@@ -235,7 +236,8 @@ static struct Section *getSection(char const *pzName, enum SectionType type,
 					     pSect->pzName);
 				else
 					fail("Section \"%s\" already declared as aligned to %u bytes",
-					     pSect->pzName, 1 << pSect->nAlign);
+					     pSect->pzName,
+					     1U << pSect->nAlign);
 			}
 		}
 
@@ -359,12 +361,12 @@ void sect_AlignPC(uint8_t alignment, uint16_t offset)
 
 	if (sect->nOrg != -1) {
 		if ((sym_GetPCValue() - offset) % (1 << alignment))
-			yyerror("Section's fixed address fails required alignment (PC = $%04x)",
+			yyerror("Section's fixed address fails required alignment (PC = $%04" PRIx32 ")",
 				sym_GetPCValue());
 	} else if (sect->nAlign != 0) {
 		if ((((sect->alignOfs + curOffset) % (1 << sect->nAlign))
 						- offset) % (1 << alignment)) {
-			yyerror("Section's alignment fails required alignment (offset from section start = $%04x)",
+			yyerror("Section's alignment fails required alignment (offset from section start = $%04" PRIx32 ")",
 				curOffset);
 		} else if (alignment > sect->nAlign) {
 			sect->nAlign = alignment;
@@ -560,7 +562,7 @@ void out_PCRelByte(struct Expression *expr)
 		int16_t offset = expr->nVal - address;
 
 		if (offset < -128 || offset > 127) {
-			yyerror("jr target out of reach (expected -129 < %d < 128)",
+			yyerror("jr target out of reach (expected -129 < %" PRId16 " < 128)",
 				offset);
 			writebyte(0);
 		} else {
@@ -616,12 +618,13 @@ void out_BinaryFile(char const *s)
 void out_BinaryFileSlice(char const *s, int32_t start_pos, int32_t length)
 {
 	if (start_pos < 0) {
-		yyerror("Start position cannot be negative (%d)", start_pos);
+		yyerror("Start position cannot be negative (%" PRId32 ")",
+			start_pos);
 		start_pos = 0;
 	}
 
 	if (length < 0) {
-		yyerror("Number of bytes to read cannot be negative (%d)",
+		yyerror("Number of bytes to read cannot be negative (%" PRId32 ")",
 			length);
 		length = 0;
 	}
@@ -676,7 +679,7 @@ void out_BinaryFileSlice(char const *s, int32_t start_pos, int32_t length)
 			yyerror("Error reading INCBIN file '%s': %s", s,
 				strerror(errno));
 		} else {
-			yyerror("Premature end of file (%d bytes left to read)",
+			yyerror("Premature end of file (%" PRId32 " bytes left to read)",
 				todo + 1);
 		}
 	}
diff --git a/src/asm/symbol.c b/src/asm/symbol.c
index 3c5c60e0..4887b364 100644
--- a/src/asm/symbol.c
+++ b/src/asm/symbol.c
@@ -12,6 +12,7 @@
 
 #include <assert.h>
 #include <errno.h>
+#include <inttypes.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
@@ -286,7 +287,7 @@ static struct Symbol *createNonrelocSymbol(char const *symbolName)
 	if (!symbol)
 		symbol = createsymbol(symbolName);
 	else if (sym_IsDefined(symbol))
-		yyerror("'%s' already defined at %s(%u)", symbolName,
+		yyerror("'%s' already defined at %s(%" PRIu32 ")", symbolName,
 			symbol->fileName, symbol->fileLine);
 
 	return symbol;
@@ -346,8 +347,8 @@ struct Symbol *sym_AddSet(char const *symName, int32_t value)
 	if (sym == NULL)
 		sym = createsymbol(symName);
 	else if (sym_IsDefined(sym) && sym->type != SYM_SET)
-		yyerror("'%s' already defined as %s at %s(%u)", symName,
-			sym->type == SYM_LABEL ? "label" : "constant",
+		yyerror("'%s' already defined as %s at %s(%" PRIu32 ")",
+			symName, sym->type == SYM_LABEL ? "label" : "constant",
 			sym->fileName, sym->fileLine);
 	else
 		/* TODO: can the scope be incorrect when talking over refs? */
@@ -407,7 +408,7 @@ struct Symbol *sym_AddReloc(char const *symName)
 	if (!sym)
 		sym = createsymbol(symName);
 	else if (sym_IsDefined(sym))
-		yyerror("'%s' already defined in %s(%d)", symName,
+		yyerror("'%s' already defined in %s(%" PRIu32 ")", symName,
 			sym->fileName, sym->fileLine);
 	/* If the symbol already exists as a ref, just "take over" it */
 
diff --git a/src/gfx/main.c b/src/gfx/main.c
index 703f7753..1b0764bc 100644
--- a/src/gfx/main.c
+++ b/src/gfx/main.c
@@ -210,7 +210,7 @@ int main(int argc, char *argv[])
 
 	if (opts.trim &&
 	    opts.trim > (raw_image->width / 8) * (raw_image->height / 8) - 1) {
-		errx(1, "Trim (%i) for input raw_image file '%s' too large (max: %i)",
+		errx(1, "Trim (%d) for input raw_image file '%s' too large (max: %u)",
 		     opts.trim, opts.infile,
 		     (raw_image->width / 8) * (raw_image->height / 8) - 1);
 	}
diff --git a/src/gfx/makepng.c b/src/gfx/makepng.c
index d8daab19..9c283116 100644
--- a/src/gfx/makepng.c
+++ b/src/gfx/makepng.c
@@ -38,7 +38,7 @@ struct RawIndexedImage *input_png_file(const struct Options *opts,
 
 	if (img.depth != depth) {
 		if (opts->verbose) {
-			warnx("Image bit depth is not %i (is %i).",
+			warnx("Image bit depth is not %d (is %d).",
 			      depth, img.depth);
 		}
 	}
diff --git a/src/link/assign.c b/src/link/assign.c
index 4ee4928f..c209ed9c 100644
--- a/src/link/assign.c
+++ b/src/link/assign.c
@@ -6,6 +6,7 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <inttypes.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
@@ -51,7 +52,7 @@ static void initFreeSpace(void)
 			memory[type][bank].next =
 				malloc(sizeof(*memory[type][0].next));
 			if (!memory[type][bank].next)
-				err(1, "Failed to init free space for region %d bank %u",
+				err(1, "Failed to init free space for region %d bank %" PRIu32,
 				    type, bank);
 			memory[type][bank].next->address = startaddr[type];
 			memory[type][bank].next->size    = maxsize[type];
@@ -304,19 +305,22 @@ static void placeSection(struct Section *section)
 
 	if (section->isBankFixed && nbbanks(section->type) != 1) {
 		if (section->isAddressFixed)
-			snprintf(where, 64, "at $%02x:%04x",
+			snprintf(where, 64, "at $%02" PRIx32 ":%04" PRIx16,
 				 section->bank, section->org);
 		else if (section->isAlignFixed)
-			snprintf(where, 64, "in bank $%02x with align mask %x",
-				 section->bank, ~section->alignMask);
+			snprintf(where, 64, "in bank $%02" PRIx32 " with align mask %" PRIx16,
+				 section->bank, (uint16_t)~section->alignMask);
 		else
-			snprintf(where, 64, "in bank $%02x", section->bank);
+			snprintf(where, 64, "in bank $%02" PRIx32,
+				 section->bank);
 	} else {
 		if (section->isAddressFixed)
-			snprintf(where, 64, "at address $%04x", section->org);
+			snprintf(where, 64, "at address $%04" PRIx16,
+				 section->org);
 		else if (section->isAlignFixed)
-			snprintf(where, 64, "with align mask %x and offset %u",
-				 ~section->alignMask, section->alignOfs);
+			snprintf(where, 64, "with align mask %" PRIx16 " and offset %" PRIx16,
+				 (uint16_t)~section->alignMask,
+				 section->alignOfs);
 		else
 			strcpy(where, "anywhere");
 	}
@@ -327,7 +331,7 @@ static void placeSection(struct Section *section)
 		     section->name, typeNames[section->type], where);
 	/* If the section just can't fit the bank, report that */
 	else if (section->org + section->size > endaddr(section->type) + 1)
-		errx(1, "Unable to place \"%s\" (%s section) %s: section runs past end of region ($%04x > $%04x)",
+		errx(1, "Unable to place \"%s\" (%s section) %s: section runs past end of region ($%04" PRIx16 " > $%04" PRIx16 ")",
 		     section->name, typeNames[section->type], where,
 		     section->org + section->size, endaddr(section->type) + 1);
 	/* Otherwise there is overlap with another section */
@@ -418,7 +422,7 @@ void assign_AssignSections(void)
 	/* Overlaying requires only fully-constrained sections */
 	verbosePrint("Assigning other sections...\n");
 	if (overlayFileName)
-		errx(1, "All sections must be fixed when using an overlay file; %lu %sn't",
+		errx(1, "All sections must be fixed when using an overlay file; %" PRIu64 " %sn't",
 		     nbSectionsToAssign, nbSectionsToAssign == 1 ? "is" : "are");
 
 	/* Assign all remaining sections by decreasing constraint order */
diff --git a/src/link/main.c b/src/link/main.c
index 41754679..4f0bef39 100644
--- a/src/link/main.c
+++ b/src/link/main.c
@@ -6,12 +6,13 @@
  * SPDX-License-Identifier: MIT
  */
 
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <stdio.h>
+#include <inttypes.h>
 #include <stdbool.h>
+#include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 
 #include "link/object.h"
 #include "link/symbol.h"
@@ -65,7 +66,7 @@ noreturn_ void fatal(char const *fmt, ...)
 	if (nbErrors != UINT32_MAX)
 		nbErrors++;
 
-	fprintf(stderr, "Linking aborted after %u error%s\n", nbErrors,
+	fprintf(stderr, "Linking aborted after %" PRIu32 " error%s\n", nbErrors,
 		nbErrors != 1 ? "s" : "");
 	exit(1);
 }
@@ -245,8 +246,8 @@ int main(int argc, char *argv[])
 	/* and finally output the result. */
 	patch_ApplyPatches();
 	if (nbErrors) {
-		fprintf(stderr, "Linking failed with %u error%s\n", nbErrors,
-			nbErrors != 1 ? "s" : "");
+		fprintf(stderr, "Linking failed with %" PRIu32 " error%s\n",
+			nbErrors, nbErrors != 1 ? "s" : "");
 		exit(1);
 	}
 	out_WriteFiles();
diff --git a/src/link/object.c b/src/link/object.c
index 360a986e..8bd949e0 100644
--- a/src/link/object.c
+++ b/src/link/object.c
@@ -6,12 +6,13 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdint.h>
 #include <string.h>
 #include <stdlib.h>
-#include <errno.h>
-#include <limits.h>
 
 #include "link/assign.h"
 #include "link/main.h"
@@ -212,25 +213,25 @@ static void readPatch(FILE *file, struct Patch *patch, char const *fileName,
 		      struct Section *fileSections[])
 {
 	tryReadstr(patch->fileName, file,
-		   "%s: Unable to read \"%s\"'s patch #%u's name: %s",
+		   "%s: Unable to read \"%s\"'s patch #%" PRIu32 "'s name: %s",
 		   fileName, sectName, i);
 	tryReadlong(patch->offset, file,
-		    "%s: Unable to read \"%s\"'s patch #%u's offset: %s",
+		    "%s: Unable to read \"%s\"'s patch #%" PRIu32 "'s offset: %s",
 		    fileName, sectName, i);
 	tryReadlong(patch->pcSectionID, file,
-		    "%s: Unable to read \"%s\"'s patch #%u's PC offset: %s",
+		    "%s: Unable to read \"%s\"'s patch #%" PRIu32 "'s PC offset: %s",
 		    fileName, sectName, i);
 	patch->pcSection = patch->pcSectionID == -1
 					? NULL
 					: fileSections[patch->pcSectionID];
 	tryReadlong(patch->pcOffset, file,
-		    "%s: Unable to read \"%s\"'s patch #%u's PC offset: %s",
+		    "%s: Unable to read \"%s\"'s patch #%" PRIu32 "'s PC offset: %s",
 		    fileName, sectName, i);
 	tryGetc(patch->type, file,
-		"%s: Unable to read \"%s\"'s patch #%u's type: %s",
+		"%s: Unable to read \"%s\"'s patch #%" PRIu32 "'s type: %s",
 		fileName, sectName, i);
 	tryReadlong(patch->rpnSize, file,
-		    "%s: Unable to read \"%s\"'s patch #%u's RPN size: %s",
+		    "%s: Unable to read \"%s\"'s patch #%" PRIu32 "'s RPN size: %s",
 		    fileName, sectName, i);
 
 	uint8_t *rpnExpression =
@@ -239,7 +240,7 @@ static void readPatch(FILE *file, struct Patch *patch, char const *fileName,
 				      patch->rpnSize, file);
 
 	if (nbElementsRead != patch->rpnSize)
-		errx(1, "%s: Cannot read \"%s\"'s patch #%u's RPN expression: %s",
+		errx(1, "%s: Cannot read \"%s\"'s patch #%" PRIu32 "'s RPN expression: %s",
 		     fileName, sectName, i,
 		     feof(file) ? "Unexpected end of file" : strerror(errno));
 	patch->rpnExpression = rpnExpression;
@@ -262,8 +263,8 @@ static void readSection(FILE *file, struct Section *section,
 	tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s' size: %s",
 		    fileName, section->name);
 	if (tmp < 0 || tmp > UINT16_MAX)
-		errx(1, "\"%s\"'s section size (%d) is invalid", section->name,
-		     tmp);
+		errx(1, "\"%s\"'s section size (%" PRId32 ") is invalid",
+		     section->name, tmp);
 	section->size = tmp;
 	tryGetc(byte, file, "%s: Cannot read \"%s\"'s type: %s",
 		fileName, section->name);
@@ -273,7 +274,8 @@ static void readSection(FILE *file, struct Section *section,
 		    fileName, section->name);
 	section->isAddressFixed = tmp >= 0;
 	if (tmp > UINT16_MAX) {
-		error("\"%s\"'s org is too large (%d)", section->name, tmp);
+		error("\"%s\"'s org is too large (%" PRId32 ")",
+		      section->name, tmp);
 		tmp = UINT16_MAX;
 	}
 	section->org = tmp;
@@ -288,7 +290,7 @@ static void readSection(FILE *file, struct Section *section,
 	tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s alignment offset: %s",
 		    fileName, section->name);
 	if (tmp > UINT16_MAX) {
-		error("\"%s\"'s alignment offset is too large (%d)",
+		error("\"%s\"'s alignment offset is too large (%" PRId32 ")",
 		      section->name, tmp);
 		tmp = UINT16_MAX;
 	}
@@ -371,7 +373,7 @@ static void readAssertion(FILE *file, struct Assertion *assert,
 {
 	char assertName[sizeof("Assertion #" EXPAND_AND_STR(UINT32_MAX))];
 
-	snprintf(assertName, sizeof(assertName), "Assertion #%u", i);
+	snprintf(assertName, sizeof(assertName), "Assertion #%" PRIu32, i);
 
 	readPatch(file, &assert->patch, fileName, assertName, 0, fileSections);
 	tryReadstr(assert->message, file, "%s: Cannot read assertion's message: %s",
@@ -417,7 +419,7 @@ void obj_ReadFile(char const *fileName)
 	tryReadlong(revNum, file, "%s: Cannot read revision number: %s",
 		    fileName);
 	if (revNum != RGBDS_OBJECT_REV)
-		errx(1, "%s is a revision 0x%04x object file, only 0x%04x is supported",
+		errx(1, "%s is a revision 0x%04" PRIx32 " object file; only 0x%04x is supported",
 		     fileName, revNum, RGBDS_OBJECT_REV);
 
 	uint32_t nbSymbols;
@@ -450,7 +452,7 @@ void obj_ReadFile(char const *fileName)
 
 	memset(nbSymPerSect, 0, sizeof(nbSymPerSect));
 
-	verbosePrint("Reading %u symbols...\n", nbSymbols);
+	verbosePrint("Reading %" PRIu32 " symbols...\n", nbSymbols);
 	for (uint32_t i = 0; i < nbSymbols; i++) {
 		/* Read symbol */
 		struct Symbol *symbol = malloc(sizeof(*symbol));
@@ -469,7 +471,7 @@ void obj_ReadFile(char const *fileName)
 	/* This file's sections, stored in a table to link symbols to them */
 	struct Section *fileSections[nbSections ? nbSections : 1];
 
-	verbosePrint("Reading %u sections...\n", nbSections);
+	verbosePrint("Reading %" PRIu32 " sections...\n", nbSections);
 	for (uint32_t i = 0; i < nbSections; i++) {
 		/* Read section */
 		fileSections[i] = malloc(sizeof(*fileSections[i]));
@@ -511,7 +513,7 @@ void obj_ReadFile(char const *fileName)
 
 	tryReadlong(nbAsserts, file, "%s: Cannot read number of assertions: %s",
 		    fileName);
-	verbosePrint("Reading %u assertions...\n", nbAsserts);
+	verbosePrint("Reading %" PRIu32 " assertions...\n", nbAsserts);
 	for (uint32_t i = 0; i < nbAsserts; i++) {
 		struct Assertion *assertion = malloc(sizeof(*assertion));
 
diff --git a/src/link/output.c b/src/link/output.c
index 5c6cc7cf..ee1c3e53 100644
--- a/src/link/output.c
+++ b/src/link/output.c
@@ -6,8 +6,9 @@
  * SPDX-License-Identifier: MIT
  */
 
-#include <stdlib.h>
+#include <inttypes.h>
 #include <stdint.h>
+#include <stdlib.h>
 
 #include "link/output.h"
 #include "link/main.h"
@@ -51,7 +52,7 @@ void out_AddSection(struct Section const *section)
 	uint32_t minNbBanks = targetBank + 1;
 
 	if (minNbBanks > maxNbBanks[section->type])
-		errx(1, "Section \"%s\" has invalid bank range (%u > %u)",
+		errx(1, "Section \"%s\" has an invalid bank range (%" PRIu32 " > %" PRIu32 ")",
 		     section->name, section->bank,
 		     maxNbBanks[section->type] - 1);
 
@@ -283,7 +284,7 @@ static void writeSymBank(struct SortedSections const *bankSections)
 
 			minSectList = &zlSectList;
 		}
-		fprintf(symFile, "%02x:%04x %s\n",
+		fprintf(symFile, "%02" PRIx32 ":%04" PRIx16 " %s\n",
 			minSectList->sect->bank, minSectList->addr,
 			minSectList->sym->name);
 		minSectList->i++;
@@ -304,7 +305,7 @@ static void writeMapBank(struct SortedSections const *sectList,
 	struct SortedSection const *section        = sectList->sections;
 	struct SortedSection const *zeroLenSection = sectList->zeroLenSections;
 
-	fprintf(mapFile, "%s bank #%u:\n", typeNames[type],
+	fprintf(mapFile, "%s bank #%" PRIu32 ":\n", typeNames[type],
 		bank + bankranges[type][0]);
 
 	uint16_t slack = maxsize[type];
@@ -317,16 +318,16 @@ static void writeMapBank(struct SortedSections const *sectList,
 		slack -= sect->size;
 
 		if (sect->size != 0)
-			fprintf(mapFile, "  SECTION: $%04x-$%04x ($%04x byte%s) [\"%s\"]\n",
+			fprintf(mapFile, "  SECTION: $%04" PRIx16 "-$%04" PRIx16 " ($%04" PRIx16 " byte%s) [\"%s\"]\n",
 				sect->org, sect->org + sect->size - 1,
 				sect->size, sect->size == 1 ? "" : "s",
 				sect->name);
 		else
-			fprintf(mapFile, "  SECTION: $%04x (0 bytes) [\"%s\"]\n",
+			fprintf(mapFile, "  SECTION: $%04" PRIx16 " (0 bytes) [\"%s\"]\n",
 				sect->org, sect->name);
 
 		for (size_t i = 0; i < sect->nbSymbols; i++)
-			fprintf(mapFile, "           $%04x = %s\n",
+			fprintf(mapFile, "           $%04" PRIx32 " = %s\n",
 				sect->symbols[i]->offset + sect->org,
 				sect->symbols[i]->name);
 
@@ -336,7 +337,7 @@ static void writeMapBank(struct SortedSections const *sectList,
 	if (slack == maxsize[type])
 		fputs("  EMPTY\n\n", mapFile);
 	else
-		fprintf(mapFile, "    SLACK: $%04x byte%s\n\n", slack,
+		fprintf(mapFile, "    SLACK: $%04" PRIx16 " byte%s\n\n", slack,
 			slack == 1 ? "" : "s");
 }
 
diff --git a/src/link/patch.c b/src/link/patch.c
index 7fa63417..09198e47 100644
--- a/src/link/patch.c
+++ b/src/link/patch.c
@@ -6,8 +6,9 @@
  * SPDX-License-Identifier: MIT
  */
 
-#include <stdlib.h>
+#include <inttypes.h>
 #include <limits.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "link/patch.h"
@@ -316,7 +317,7 @@ static int32_t computeRPNExpr(struct Patch const *patch,
 			if (value < 0
 			 || (value > 0xFF && value < 0xFF00)
 			 || value > 0xFFFF)
-				error("%s: Value %d is not in HRAM range",
+				error("%s: Value %" PRId32 " is not in HRAM range",
 				      patch->fileName, value);
 			value &= 0xFF;
 			break;
@@ -327,7 +328,7 @@ static int32_t computeRPNExpr(struct Patch const *patch,
 			 * They can be easily checked with a bitmask
 			 */
 			if (value & ~0x38)
-				error("%s: Value %d is not a RST vector",
+				error("%s: Value %" PRId32 " is not a RST vector",
 				      patch->fileName, value);
 			value |= 0xC7;
 			break;
@@ -370,7 +371,7 @@ static int32_t computeRPNExpr(struct Patch const *patch,
 	}
 
 	if (stack.size > 1)
-		error("%s: RPN stack has %lu entries on exit, not 1",
+		error("%s: RPN stack has %zu entries on exit, not 1",
 		      patch->fileName, stack.size);
 
 	return popRPN();
@@ -440,7 +441,7 @@ static void applyFilePatches(struct Section *section)
 			int16_t offset = value - address;
 
 			if (offset < -128 || offset > 127)
-				error("%s: jr target out of reach (expected -129 < %d < 128)",
+				error("%s: jr target out of reach (expected -129 < %" PRId16 " < 128)",
 				      patch->fileName, offset);
 			section->data[patch->offset] = offset & 0xFF;
 		} else {
@@ -457,10 +458,10 @@ static void applyFilePatches(struct Section *section)
 
 			if (value < types[patch->type].min
 			 || value > types[patch->type].max)
-				error("%s: Value %#x%s is not %u-bit",
+				error("%s: Value %#" PRIx32 "%s is not %u-bit",
 				      patch->fileName, value,
 				      value < 0 ? " (maybe negative?)" : "",
-				      types[patch->type].size * 8);
+				      types[patch->type].size * 8U);
 			for (uint8_t i = 0; i < types[patch->type].size; i++) {
 				section->data[patch->offset + i] = value & 0xFF;
 				value >>= 8;
diff --git a/src/link/script.c b/src/link/script.c
index b51e9bb3..75c4f50a 100644
--- a/src/link/script.c
+++ b/src/link/script.c
@@ -6,11 +6,12 @@
  * SPDX-License-Identifier: MIT
  */
 
-#include <stdlib.h>
+#include <ctype.h>
+#include <inttypes.h>
 #include <stdbool.h>
 #include <stdint.h>
+#include <stdlib.h>
 #include <string.h>
-#include <ctype.h>
 
 #include "link/main.h"
 #include "link/script.h"
@@ -35,7 +36,7 @@ static uint32_t fileStackIndex;
 static void pushFile(char *newFileName)
 {
 	if (fileStackIndex == UINT32_MAX)
-		errx(1, "%s(%u): INCLUDE recursion limit reached",
+		errx(1, "%s(%" PRIu32 "): INCLUDE recursion limit reached",
 		     linkerScriptName, lineNo);
 
 	if (fileStackIndex == fileStackSize) {
@@ -45,7 +46,7 @@ static void pushFile(char *newFileName)
 		fileStack = realloc(fileStack,
 				    sizeof(*fileStack) * fileStackSize);
 		if (!fileStack)
-			err(1, "%s(%u): Internal INCLUDE error",
+			err(1, "%s(%" PRIu32 "): Internal INCLUDE error",
 			    linkerScriptName, lineNo);
 	}
 
@@ -56,7 +57,7 @@ static void pushFile(char *newFileName)
 
 	linkerScript = fopen(newFileName, "r");
 	if (!linkerScript)
-		err(1, "%s(%u): Could not open \"%s\"",
+		err(1, "%s(%" PRIu32 "): Could not open \"%s\"",
 		    linkerScriptName, lineNo, newFileName);
 	lineNo = 1;
 	linkerScriptName = newFileName;
@@ -177,8 +178,8 @@ static int readChar(FILE *file)
 	int curchar = getc(file);
 
 	if (curchar == EOF && ferror(file))
-		err(1, "%s(%u): Unexpected error in %s", linkerScriptName,
-		    lineNo, __func__);
+		err(1, "%s(%" PRIu32 "): Unexpected error in %s",
+		    linkerScriptName, lineNo, __func__);
 	return curchar;
 }
 
@@ -223,7 +224,7 @@ static struct LinkerScriptToken *nextToken(void)
 		do {
 			curchar = readChar(linkerScript);
 			if (curchar == EOF || isNewline(curchar))
-				errx(1, "%s(%u): Unterminated string",
+				errx(1, "%s(%" PRIu32 "): Unterminated string",
 				     linkerScriptName, lineNo);
 			else if (curchar == '"')
 				/* Quotes force a string termination */
@@ -302,7 +303,7 @@ static struct LinkerScriptToken *nextToken(void)
 			if (tryParseNumber(str, &token.attr.number))
 				token.type = TOKEN_NUMBER;
 			else
-				errx(1, "%s(%u): Unknown token \"%s\"",
+				errx(1, "%s(%" PRIu32 "): Unknown token \"%s\"",
 				     linkerScriptName, lineNo, str);
 		}
 
@@ -330,7 +331,7 @@ static void processCommand(enum LinkerScriptCommand command, uint16_t arg,
 	}
 
 	if (arg < *pc)
-		errx(1, "%s(%u): `%s` cannot be used to go backwards",
+		errx(1, "%s(%" PRIu32 "): `%s` cannot be used to go backwards",
 		     linkerScriptName, lineNo, commands[command]);
 	*pc = arg;
 }
@@ -379,11 +380,11 @@ struct SectionPlacement *script_NextSection(void)
 
 		if (type != SECTTYPE_INVALID) {
 			if (curaddr[type][bankID] > endaddr(type) + 1)
-				errx(1, "%s(%u): Sections would extend past the end of %s ($%04hx > $%04hx)",
+				errx(1, "%s(%" PRIu32 "): Sections would extend past the end of %s ($%04" PRIx16 " > $%04" PRIx16 ")",
 				     linkerScriptName, lineNo, typeNames[type],
 				     curaddr[type][bankID], endaddr(type));
 			if (curaddr[type][bankID] < startaddr[type])
-				errx(1, "%s(%u): PC underflowed ($%04hx < $%04hx)",
+				errx(1, "%s(%" PRIu32 "): PC underflowed ($%04" PRIx16 " < $%04" PRIx16 ")",
 				     linkerScriptName, lineNo,
 				     curaddr[type][bankID], startaddr[type]);
 		}
@@ -404,7 +405,7 @@ struct SectionPlacement *script_NextSection(void)
 				break;
 
 			case TOKEN_NUMBER:
-				errx(1, "%s(%u): stray number \"%u\"",
+				errx(1, "%s(%" PRIu32 "): stray number \"%" PRIu32 "\"",
 				     linkerScriptName, lineNo,
 				     token->attr.number);
 
@@ -417,13 +418,13 @@ struct SectionPlacement *script_NextSection(void)
 				parserState = PARSER_LINEEND;
 
 				if (type == SECTTYPE_INVALID)
-					errx(1, "%s(%u): Didn't specify a location before the section",
+					errx(1, "%s(%" PRIu32 "): Didn't specify a location before the section",
 					     linkerScriptName, lineNo);
 
 				section.section =
 					sect_GetSection(token->attr.string);
 				if (!section.section)
-					errx(1, "%s(%u): Unknown section \"%s\"",
+					errx(1, "%s(%" PRIu32 "): Unknown section \"%s\"",
 					     linkerScriptName, lineNo,
 					     token->attr.string);
 				section.org = curaddr[type][bankID];
@@ -452,10 +453,10 @@ struct SectionPlacement *script_NextSection(void)
 
 				if (tokType == TOKEN_COMMAND) {
 					if (type == SECTTYPE_INVALID)
-						errx(1, "%s(%u): Didn't specify a location before the command",
+						errx(1, "%s(%" PRIu32 "): Didn't specify a location before the command",
 						     linkerScriptName, lineNo);
 					if (!hasArg)
-						errx(1, "%s(%u): Command specified without an argument",
+						errx(1, "%s(%" PRIu32 "): Command specified without an argument",
 						     linkerScriptName, lineNo);
 
 					processCommand(attr.command, arg,
@@ -467,16 +468,16 @@ struct SectionPlacement *script_NextSection(void)
 					 * specifying the number is optional.
 					 */
 					if (!hasArg && nbbanks(type) != 1)
-						errx(1, "%s(%u): Didn't specify a bank number",
+						errx(1, "%s(%" PRIu32 "): Didn't specify a bank number",
 						     linkerScriptName, lineNo);
 					else if (!hasArg)
 						arg = bankranges[type][0];
 					else if (arg < bankranges[type][0])
-						errx(1, "%s(%u): specified bank number is too low (%u < %u)",
+						errx(1, "%s(%" PRIu32 "): specified bank number is too low (%" PRIu32 " < %" PRIu32 ")",
 						     linkerScriptName, lineNo,
 						     arg, bankranges[type][0]);
 					else if (arg > bankranges[type][1])
-						errx(1, "%s(%u): specified bank number is too high (%u > %u)",
+						errx(1, "%s(%" PRIu32 "): specified bank number is too high (%" PRIu32 " > %" PRIu32 ")",
 						     linkerScriptName, lineNo,
 						     arg, bankranges[type][1]);
 					bank = arg;
@@ -496,7 +497,7 @@ struct SectionPlacement *script_NextSection(void)
 
 		case PARSER_INCLUDE:
 			if (token->type != TOKEN_STRING)
-				errx(1, "%s(%u): Expected a file name after INCLUDE",
+				errx(1, "%s(%" PRIu32 "): Expected a file name after INCLUDE",
 				     linkerScriptName, lineNo);
 
 			/* Switch to that file */
@@ -516,7 +517,7 @@ lineend:
 					return NULL;
 				parserState = PARSER_LINEEND;
 			} else if (token->type != TOKEN_NEWLINE)
-				errx(1, "%s(%u): Unexpected %s at the end of the line",
+				errx(1, "%s(%" PRIu32 "): Unexpected %s at the end of the line",
 				     linkerScriptName, lineNo,
 				     tokenTypes[token->type]);
 			break;
diff --git a/src/link/section.c b/src/link/section.c
index 59a71348..fb344e6d 100644
--- a/src/link/section.c
+++ b/src/link/section.c
@@ -6,6 +6,7 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <inttypes.h>
 #include <stdbool.h>
 
 #include "link/main.h"
@@ -45,11 +46,11 @@ static void mergeSections(struct Section *target, struct Section *other)
 	if (other->isAddressFixed) {
 		if (target->isAddressFixed) {
 			if (target->org != other->org)
-				errx(1, "Section \"%s\" is defined with conflicting addresses $%x and $%x",
+				errx(1, "Section \"%s\" is defined with conflicting addresses $%" PRIx16 " and $%" PRIx16,
 				     other->name, target->org, other->org);
 		} else if (target->isAlignFixed) {
 			if ((other->org - target->alignOfs) & target->alignMask)
-				errx(1, "Section \"%s\" is defined with conflicting %u-byte alignment (offset %u) and address $%x",
+				errx(1, "Section \"%s\" is defined with conflicting %" PRIu16 "-byte alignment (offset %" PRIu16 ") and address $%" PRIx16,
 				     other->name, target->alignMask + 1,
 				     target->alignOfs, other->org);
 		}
@@ -58,13 +59,13 @@ static void mergeSections(struct Section *target, struct Section *other)
 	} else if (other->isAlignFixed) {
 		if (target->isAddressFixed) {
 			if ((target->org - other->alignOfs) & other->alignMask)
-				errx(1, "Section \"%s\" is defined with conflicting address $%x and %u-byte alignment (offset %u)",
+				errx(1, "Section \"%s\" is defined with conflicting address $%" PRIx16 " and %" PRIu16 "-byte alignment (offset %" PRIu16 ")",
 				     other->name, target->org,
 				     other->alignMask + 1, other->alignOfs);
 		} else if (target->isAlignFixed
 			&& (other->alignMask & target->alignOfs)
 				 != (target->alignMask & other->alignOfs)) {
-			errx(1, "Section \"%s\" is defined with conflicting %u-byte alignment (offset %u) and %u-byte alignment (offset %u)",
+			errx(1, "Section \"%s\" is defined with conflicting %" PRIu16 "-byte alignment (offset %" PRIu16 ") and %" PRIu16 "-byte alignment (offset %" PRIu16 ")",
 			     other->name, target->alignMask + 1,
 			     target->alignOfs, other->alignMask + 1,
 			     other->alignOfs);
@@ -80,7 +81,7 @@ static void mergeSections(struct Section *target, struct Section *other)
 			target->isBankFixed = true;
 			target->bank = other->bank;
 		} else if (target->bank != other->bank) {
-			errx(1, "Section \"%s\" is defined with conflicting banks %u and %u",
+			errx(1, "Section \"%s\" is defined with conflicting banks %" PRIu32 " and %" PRIu32,
 			     other->name, target->bank, other->bank);
 		}
 	}
@@ -171,7 +172,7 @@ static void doSanityChecks(struct Section *section, void *ptr)
 	/* Too large an alignment may not be satisfiable */
 	if (section->isAlignFixed
 	 && (section->alignMask & startaddr[section->type]))
-		fail("%s: %s sections cannot be aligned to $%x bytes",
+		fail("%s: %s sections cannot be aligned to $%" PRIx16 " bytes",
 		     section->name, typeNames[section->type],
 		     section->alignMask + 1);
 
@@ -181,13 +182,13 @@ static void doSanityChecks(struct Section *section, void *ptr)
 	if (section->isBankFixed && section->bank < minbank
 				 && section->bank > maxbank)
 		fail(minbank == maxbank
-			? "Cannot place section \"%s\" in bank %d, it must be %d"
-			: "Cannot place section \"%s\" in bank %d, it must be between %d and %d",
+			? "Cannot place section \"%s\" in bank %" PRIu32 ", it must be %" PRIu32
+			: "Cannot place section \"%s\" in bank %" PRIu32 ", it must be between %" PRIu32 " and %" PRIu32,
 		     section->name, section->bank, minbank, maxbank);
 
 	/* Check if section has a chance to be placed */
 	if (section->size > maxsize[section->type])
-		fail("Section \"%s\" is bigger than the max size for that type: %#x > %#x",
+		fail("Section \"%s\" is bigger than the max size for that type: %#" PRIx16 " > %#" PRIx16,
 		     section->name, section->size, maxsize[section->type]);
 
 	/* Translate loose constraints to strong ones when they're equivalent */
@@ -218,12 +219,12 @@ static void doSanityChecks(struct Section *section, void *ptr)
 		/* Ensure the target address is valid */
 		if (section->org < startaddr[section->type]
 		 || section->org > endaddr(section->type))
-			fail("Section \"%s\"'s fixed address %#x is outside of range [%#x; %#x]",
+			fail("Section \"%s\"'s fixed address %#" PRIx16 " is outside of range [%#" PRIx16 "; %#" PRIx16 "]",
 			     section->name, section->org,
 			     startaddr[section->type], endaddr(section->type));
 
 		if (section->org + section->size > endaddr(section->type) + 1)
-			fail("Section \"%s\"'s end address %#x is greater than last address %#x",
+			fail("Section \"%s\"'s end address %#" PRIx16 " is greater than last address %#" PRIx16,
 			     section->name, section->org + section->size,
 			     endaddr(section->type) + 1);
 	}
diff --git a/src/link/symbol.c b/src/link/symbol.c
index 5bda0fd9..051a7db9 100644
--- a/src/link/symbol.c
+++ b/src/link/symbol.c
@@ -6,6 +6,7 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <inttypes.h>
 #include <stdbool.h>
 
 #include "link/symbol.h"
@@ -40,7 +41,7 @@ void sym_AddSymbol(struct Symbol *symbol)
 	struct Symbol *other = hash_GetElement(symbols, symbol->name);
 
 	if (other)
-		errx(1, "\"%s\" both in %s from %s(%d) and in %s from %s(%d)",
+		errx(1, "\"%s\" both in %s from %s(%" PRId32 ") and in %s from %s(%" PRId32 ")",
 		     symbol->name,
 		     symbol->objFileName, symbol->fileName, symbol->lineNo,
 		      other->objFileName,  other->fileName,  other->lineNo);
diff --git a/test/asm/pc-bank.err b/test/asm/pc-bank.err
index 3c165fb9..2b8a1c85 100644
--- a/test/asm/pc-bank.err
+++ b/test/asm/pc-bank.err
@@ -1,5 +1,5 @@
 ERROR: pc-bank.asm(2):
-    Source address $2a00 not in $FF00 to $FFFF
+    Source address $2a00 not between $FF00 to $FFFF
 ERROR: pc-bank.asm(11):
     Expected constant expression: Current section's bank is not known
 error: Assembly aborted (2 errors)!
diff --git a/test/link/section-union/no-room.out b/test/link/section-union/no-room.out
index 4a1104da..e14ba53a 100644
--- a/test/link/section-union/no-room.out
+++ b/test/link/section-union/no-room.out
@@ -1,2 +1,2 @@
-error: Unable to place "test" (WRAMX section) in bank $02 with align mask ffffffc0
+error: Unable to place "test" (WRAMX section) in bank $02 with align mask ffc0
 ---