diff --git a/zsnes/src/cpu/regs.inc b/zsnes/src/cpu/regs.inc
index 3a2fc749..6fc713e0 100644
--- a/zsnes/src/cpu/regs.inc
+++ b/zsnes/src/cpu/regs.inc
@@ -919,6 +919,10 @@ reg4210r:
 reg4211r:
     mov al,[irqon]
     mov byte[irqon],0
+    cmp dh,[cycphb]
+    jae .nohblank
+    or al,40h
+.nohblank
     ret
 
 ; H/V Blank Flag & Joystick Controller Enable Flag