diff --git a/CHANGES b/CHANGES
index 0b7e7babd..6174d43e7 100644
--- a/CHANGES
+++ b/CHANGES
@@ -32,6 +32,7 @@ Bugfixes:
  - GBA Timer: Fix timers sometimes being late (fixes mgba.io/i/1012)
  - GBA Hardware: Fix RTC overriding light sensor (fixes mgba.io/i/1069)
  - GBA Savedata: Fix savedata modified time updating when read-only
+ - GB Video: Fix enabling window when LY > WY (fixes mgba.io/i/409)
 Misc:
  - GBA Timer: Use global cycles for timers
  - GBA: Extend oddly-sized ROMs to full address space (fixes mgba.io/i/722)
diff --git a/cinema/gb/window/wmm-hud/baseline_0000.png b/cinema/gb/window/wmm-hud/baseline_0000.png
new file mode 100644
index 000000000..15207ebdc
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diff --git a/cinema/gb/window/wmm-hud/baseline_0001.png b/cinema/gb/window/wmm-hud/baseline_0001.png
new file mode 100644
index 000000000..15207ebdc
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diff --git a/cinema/gb/window/wmm-hud/baseline_0002.png b/cinema/gb/window/wmm-hud/baseline_0002.png
new file mode 100644
index 000000000..15207ebdc
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diff --git a/cinema/gb/window/wmm-hud/baseline_0003.png b/cinema/gb/window/wmm-hud/baseline_0003.png
new file mode 100644
index 000000000..7c0d4bc3b
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diff --git a/cinema/gb/window/wmm-hud/baseline_0004.png b/cinema/gb/window/wmm-hud/baseline_0004.png
new file mode 100644
index 000000000..7c0d4bc3b
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diff --git a/cinema/gb/window/wmm-hud/baseline_0005.png b/cinema/gb/window/wmm-hud/baseline_0005.png
new file mode 100644
index 000000000..7c0d4bc3b
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diff --git a/cinema/gb/window/wmm-hud/baseline_0006.png b/cinema/gb/window/wmm-hud/baseline_0006.png
new file mode 100644
index 000000000..7c0d4bc3b
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diff --git a/cinema/gb/window/wmm-hud/baseline_0007.png b/cinema/gb/window/wmm-hud/baseline_0007.png
new file mode 100644
index 000000000..7c0d4bc3b
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diff --git a/cinema/gb/window/wmm-hud/test.mvl b/cinema/gb/window/wmm-hud/test.mvl
new file mode 100644
index 000000000..b57da961e
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diff --git a/src/gb/renderers/software.c b/src/gb/renderers/software.c
index f63939113..8ca44026b 100644
--- a/src/gb/renderers/software.c
+++ b/src/gb/renderers/software.c
@@ -229,7 +229,11 @@ static void GBVideoSoftwareRendererUpdateWindow(struct GBVideoSoftwareRenderer*
 			renderer->hasWindow = true;
 		} else {
 			if (!renderer->hasWindow) {
-				renderer->currentWy = renderer->lastY - renderer->wy;
+				if (renderer->lastY > renderer->wy) {
+					renderer->currentWy = GB_VIDEO_VERTICAL_PIXELS;
+				} else {
+					renderer->currentWy = renderer->lastY - renderer->wy;
+				}
 			} else {
 				renderer->currentWy += renderer->lastY;
 			}