diff --git a/src/gba/gba.c b/src/gba/gba.c
index 9b3ee9165..3bfdb4eec 100644
--- a/src/gba/gba.c
+++ b/src/gba/gba.c
@@ -734,12 +734,12 @@ bool GBAIsMB(struct VFile* vf) {
 	if (vf->seek(vf, GBA_MB_MAGIC_OFFSET, SEEK_SET) < 0) {
 		return false;
 	}
-	uint8_t signature[sizeof(uint32_t)];
+	uint32_t signature;
 	if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
 		return false;
 	}
 	uint32_t opcode;
-	LOAD_32(opcode, 0, signature);
+	LOAD_32(opcode, 0, &signature);
 	struct ARMInstructionInfo info;
 	ARMDecodeARM(opcode, &info);
 	if (info.branchType != ARM_BRANCH) {