diff --git a/engine/gfx/cgb_layouts.asm b/engine/gfx/cgb_layouts.asm
index ea2f1455c..9a5238099 100644
--- a/engine/gfx/cgb_layouts.asm
+++ b/engine/gfx/cgb_layouts.asm
@@ -509,6 +509,7 @@ _CGB_BetaPoker:
 _CGB_Diploma:
 	ld hl, DiplomaPalettes
 	ld de, wBGPals1
+	assert DiplomaPalettes + 8 palettes == PartyMenuOBPals
 	ld bc, 16 palettes
 	ld a, BANK(wBGPals1)
 	call FarCopyWRAM