diff --git a/Source/3rdParty/mupen64plus-core/src/main/rom.c b/Source/3rdParty/mupen64plus-core/src/main/rom.c
index 445610a9..f479cf1d 100644
--- a/Source/3rdParty/mupen64plus-core/src/main/rom.c
+++ b/Source/3rdParty/mupen64plus-core/src/main/rom.c
@@ -76,12 +76,16 @@ static const uint8_t Z64_SIGNATURE[4] = { 0x80, 0x37, 0x12, 0x40 };
 static const uint8_t V64_SIGNATURE[4] = { 0x37, 0x80, 0x40, 0x12 };
 static const uint8_t N64_SIGNATURE[4] = { 0x40, 0x12, 0x37, 0x80 };
 
+static const uint8_t ALT_Z64_SIGNATURE[4] = { 0x31, 0x37, 0x12, 0x40 };
+
 /* Tests if a file is a valid N64 rom by checking the first 4 bytes and size */
 static int is_valid_rom(const unsigned char *buffer, unsigned int size)
 {
+    printf("rom signature: 0x%02X, 0x%02X, 0x%02X, 0x%02X\n", buffer[0], buffer[1], buffer[2], buffer[3]);
     if ((memcmp(buffer, Z64_SIGNATURE, sizeof(Z64_SIGNATURE)) == 0)
      || (memcmp(buffer, V64_SIGNATURE, sizeof(V64_SIGNATURE)) == 0 && size % 2 == 0)
-     || (memcmp(buffer, N64_SIGNATURE, sizeof(N64_SIGNATURE)) == 0 && size % 4 == 0))
+     || (memcmp(buffer, N64_SIGNATURE, sizeof(N64_SIGNATURE)) == 0 && size % 4 == 0)
+     || (memcmp(buffer, ALT_Z64_SIGNATURE, sizeof(ALT_Z64_SIGNATURE)) == 0))
         return 1;
     else
         return 0;
@@ -149,6 +153,7 @@ m64p_error open_rom(const unsigned char* romimage, unsigned int size)
     if (romimage == NULL || !is_valid_rom(romimage, size))
     {
         DebugMessage(M64MSG_ERROR, "open_rom(): not a valid ROM image");
+        printf("fail\n");
         return M64ERR_INPUT_INVALID;
     }