diff --git a/src/asm/lexer.c b/src/asm/lexer.c
index 5651d42a..779618bb 100644
--- a/src/asm/lexer.c
+++ b/src/asm/lexer.c
@@ -1962,13 +1962,11 @@ restart:
 
 static char *startCapture(void)
 {
-	assert(!lexerState->expansions);
-
 	lexerState->capturing = true;
 	lexerState->captureSize = 0;
 	lexerState->disableMacroArgs = true;
 
-	if (lexerState->isMmapped) {
+	if (lexerState->isMmapped && !lexerState->expansions) {
 		return &lexerState->ptr[lexerState->offset];
 	} else {
 		lexerState->captureCapacity = 128; /* The initial size will be twice that */
diff --git a/test/asm/equs-macrodef.asm b/test/asm/equs-macrodef.asm
new file mode 100644
index 00000000..042fee23
--- /dev/null
+++ b/test/asm/equs-macrodef.asm
@@ -0,0 +1,3 @@
+DEFINE equs "mac: MACRO\nPRINTT \"Hello :D\\n\"\nENDM"
+DEFINE
+	mac
diff --git a/test/asm/equs-macrodef.err b/test/asm/equs-macrodef.err
new file mode 100644
index 00000000..e69de29b
diff --git a/test/asm/equs-macrodef.out b/test/asm/equs-macrodef.out
new file mode 100644
index 00000000..48c67c87
--- /dev/null
+++ b/test/asm/equs-macrodef.out
@@ -0,0 +1 @@
+Hello :D