diff --git a/src/video/vid_s3.c b/src/video/vid_s3.c
index 175b5048f..101d3ae8b 100644
--- a/src/video/vid_s3.c
+++ b/src/video/vid_s3.c
@@ -3527,7 +3527,7 @@ s3_in(uint16_t addr, void *priv)
                     }
                     break;
                 case 0x30:
-                    return s3->id; /*Chip ID*/
+                    return ((svga->crtc[0x38] & 0xcc) != 0x48) ? 0xFF : s3->id; /*Chip ID*/
                 case 0x31:
                     return (svga->crtc[0x31] & 0xcf) | ((s3->ma_ext & 3) << 4);
                 case 0x35:
diff --git a/src/video/vid_s3_virge.c b/src/video/vid_s3_virge.c
index cc4f75205..bb1b2b11e 100644
--- a/src/video/vid_s3_virge.c
+++ b/src/video/vid_s3_virge.c
@@ -751,7 +751,7 @@ s3_virge_in(uint16_t addr, void *priv)
                     ret = virge->virge_rev;
                     break;
                 case 0x30:
-                    ret = virge->virge_id;
+                    ret = ((svga->crtc[0x38] & 0xcc) != 0x48) ? 0xFF : virge->virge_id;
                     break; /*Chip ID*/
                 case 0x31:
                     ret = (svga->crtc[0x31] & 0xcf) | ((virge->ma_ext & 3) << 4);