diff --git a/src/vid_s3.c b/src/vid_s3.c
index da09f7c..d13da8a 100644
--- a/src/vid_s3.c
+++ b/src/vid_s3.c
@@ -908,7 +908,7 @@ uint8_t s3_accel_read(uint32_t addr, void *p)
                 {                                                                                       \
                         case 0x0: dest_dat =             ~dest_dat;  break;                             \
                         case 0x1: dest_dat =  0;                     break;                             \
-                        case 0x2: dest_dat =  1;                     break;                             \
+                        case 0x2: dest_dat = ~0;                     break;                             \
                         case 0x3: dest_dat =              dest_dat;  break;                             \
                         case 0x4: dest_dat =  ~src_dat;              break;                             \
                         case 0x5: dest_dat =   src_dat ^  dest_dat;  break;                             \