diff --git a/src/p_setup.c b/src/p_setup.c
index fd8b19f1c03c020dc7c1c197e9cfa172ad9d6a47..057ccb45e979633b7f28a3d270c6915f1bbde0d5 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -3557,10 +3557,10 @@ static void P_ConvertBinaryMap(void)
 
 			//Flags
 			if (lines[i].flags & ML_EFFECT1)
-				lines[i].args[2] = TMFL_NOBOSSES;
+				lines[i].args[2] |= TMFL_NOBOSSES;
 			//Replicate old hack: Translucent FOFs set to full opacity cut cyan pixels
 			if (lines[i].flags & ML_EFFECT6 || lines[i].args[1] == 256)
-				lines[i].args[2] = TMFL_SPLAT;
+				lines[i].args[2] |= TMFL_SPLAT;
 
 			break;
 		case 259: //Custom FOF