diff --git a/buildcfg.txt b/buildcfg.txt
index 0117c6be..f32a9ad9 100644
--- a/buildcfg.txt
+++ b/buildcfg.txt
@@ -2864,3 +2864,6 @@ AQF076
 ; Custom flats
 FCGRATE1
 FCGRATE2
+FLAT5_6B
+FLAT5_6C
+
diff --git a/levels/map26.wad b/levels/map26.wad
index 9e9de57d..e0ebf703 100644
Binary files a/levels/map26.wad and b/levels/map26.wad differ