diff --git a/src/soc/amd/common/block/graphics/graphics.c b/src/soc/amd/common/block/graphics/graphics.c
index cc52053104..d8f3e1fd86 100644
--- a/src/soc/amd/common/block/graphics/graphics.c
+++ b/src/soc/amd/common/block/graphics/graphics.c
@@ -257,11 +257,13 @@ void vbios_load_from_cache(void)
 /*
  * Return true if VBIOS cache data is valid
  *
- * Compare hash of data with hash stored in TPM NVRAM
+ * Compare first 2 bytes of data with known signature
+ * and hash of data with hash stored in TPM NVRAM
  */
 bool vbios_cache_is_valid(void)
 {
-	return vbios_cache_verify_hash(vbios_data, VBIOS_CACHE_FMAP_SIZE) == CB_SUCCESS;
+	bool sig_valid = vbios_data[0] == 0x55 && vbios_data[1] == 0xaa;
+	return sig_valid && vbios_cache_verify_hash(vbios_data, VBIOS_CACHE_FMAP_SIZE) == CB_SUCCESS;
 }
 
 BOOT_STATE_INIT_ENTRY(BS_PRE_DEVICE, BS_ON_EXIT, read_vbios_cache_from_fmap, NULL);