diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/PPU.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/PPU.cs
index b088b237a0..fdb381ae9e 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/PPU.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/PPU.cs
@@ -485,6 +485,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 					{
 						window_y_tile_inc = 0;
 						window_y_tile++;
+						window_y_tile %= 32;
 					}
 				}
 				window_started = false;