diff --git a/src/fx/fx.hgr.precomputed.1bit.a b/src/fx/fx.hgr.precomputed.1bit.a
index a221d9ff4..95ecb884b 100644
--- a/src/fx/fx.hgr.precomputed.1bit.a
+++ b/src/fx/fx.hgr.precomputed.1bit.a
@@ -5,7 +5,7 @@
 ;hgrlo          = $0201    ; $C0 bytes (defined in constants.a)
 mirror_cols    = $02C1    ; $28 bytes
 ;hgr1hi         = $0301    ; $C0 bytes (defined in constants.a)
-dithermasks    = $BBAA    ; $58 bytes
+dithermasks    = $BBA8    ; $58 bytes
 evenrow_masks  = dithermasks
 oddrow_masks   = dithermasks+2
 no_masks       = dithermasks+44
diff --git a/src/fx/fx.hgr.precomputed.2bit.a b/src/fx/fx.hgr.precomputed.2bit.a
index 886fb19b9..335616530 100644
--- a/src/fx/fx.hgr.precomputed.2bit.a
+++ b/src/fx/fx.hgr.precomputed.2bit.a
@@ -5,7 +5,7 @@
 ;hgrlo          = $0201    ; $C0 bytes (defined in constants.a)
 mirror_cols    = $02C1    ; $28 bytes
 ;hgr1hi         = $0301    ; $C0 bytes (defined in constants.a)
-dithermasks    = $BDAA    ; $58 bytes
+dithermasks    = $BDA8    ; $58 bytes
 evenrow_masks  = dithermasks
 oddrow_masks   = dithermasks+2
 no_masks       = dithermasks+44
diff --git a/src/fx/macros.dither.a b/src/fx/macros.dither.a
index affc80ccb..d7d17f917 100644
--- a/src/fx/macros.dither.a
+++ b/src/fx/macros.dither.a
@@ -19,7 +19,7 @@
          dey
          dey
          bpl   -
-         ldy   #39
+         ldy   #43
          lda   #$FF
 -        sta   .dithermasks+44, y
          dey
@@ -41,7 +41,7 @@
          dey
          dey
          bpl   -
-         ldy   #39
+         ldy   #43
 -        lda   #$FF
          sta   .dithermasks+44, y
          dey
@@ -61,11 +61,11 @@
          dey
          dey
          bpl   -
-         ldy   #39
+         ldy   #43
 -        lda   #$FF
          sta   .dithermasks+44, y
          dey
-         bne   -
+         bpl   -
          sta   $C004
 }