diff --git a/zsnes/src/video/newgfx.mac b/zsnes/src/video/newgfx.mac
index c4cf5a74..f87684a1 100644
--- a/zsnes/src/video/newgfx.mac
+++ b/zsnes/src/video/newgfx.mac
@@ -2887,7 +2887,10 @@ EXTSYM drawmode7ngextbg,drawmode7ngextbg2
     shr edx,3
     shl edx,6
     xor eax,eax
+    cmp byte[BGMA+ebx],4
+    je .offsetmode4
     mov ax,[BGPT3+ebx*2]
+.offsetmode4
     add ax,dx
     xor edx,edx
     mov dx,[BG3SXl+ebx*2]
diff --git a/zsnes/src/video/newgfx16.mac b/zsnes/src/video/newgfx16.mac
index 0271f983..f601ae60 100644
--- a/zsnes/src/video/newgfx16.mac
+++ b/zsnes/src/video/newgfx16.mac
@@ -3299,7 +3299,10 @@ EXTSYM osm2dis
     shr edx,3
     shl edx,6
     xor eax,eax
+    cmp byte[BGMA+ebx],4
+    je .offsetmode4
     mov ax,[BGPT3+ebx*2]
+.offsetmode4
     add ax,dx
     xor edx,edx
     mov dx,[BG3SXl+ebx*2]