diff --git a/wadsrc/static/compatibility.txt b/wadsrc/static/compatibility.txt
index b131cd0ad..c486b48ae 100644
--- a/wadsrc/static/compatibility.txt
+++ b/wadsrc/static/compatibility.txt
@@ -459,6 +459,25 @@ F6EE16F770AD309D608EA0B1F1E249FC // Ultimate Doom, e4m3
 {
 	setsectorspecial 124 0
 	setsectorspecial 125 0
+	// clear staircase to secret area
+	setsectorspecial 127 0
+	setsectorspecial 128 0
+	setsectorspecial 129 0
+	setsectorspecial 130 0
+	setsectorspecial 131 0
+	setsectorspecial 132 0
+	setsectorspecial 133 0
+	setsectorspecial 134 0
+	setsectorspecial 136 0
+	setsectorspecial 137 0
+	setsectorspecial 138 0
+	setsectorspecial 147 0
+	setsectorspecial 148 0
+	setsectorspecial 149 0
+	setsectorspecial 150 0
+	setsectorspecial 151 0
+	setsectorspecial 152 0
+	setsectorspecial 155 0
 }
 94D4C869A0C02EF4F7375022B36AAE45 // Ultimate Doom, e4m7
 {