diff --git a/src/vid_ati_mach64.c b/src/vid_ati_mach64.c
index f6c7720..6f92116 100644
--- a/src/vid_ati_mach64.c
+++ b/src/vid_ati_mach64.c
@@ -3210,7 +3210,10 @@ uint8_t mach64_pci_read(int func, int addr, void *p)
                 case 0x12: return mach64->linear_base >> 16;
                 case 0x13: return mach64->linear_base >> 24;
 
-                case 0x14: return 0x01; /*Block decoded IO address*/
+                case 0x14:
+                if (mach64->type == MACH64_VT2)
+                        return 0x01; /*Block decoded IO address*/
+                return 0;
                 case 0x15: return mach64->block_decoded_io >> 8;
                 case 0x16: return mach64->block_decoded_io >> 16;
                 case 0x17: return mach64->block_decoded_io >> 24;