diff --git a/src/newgrf_commons.h b/src/newgrf_commons.h
--- a/src/newgrf_commons.h
+++ b/src/newgrf_commons.h
@@ -49,7 +49,7 @@ enum TileLayoutFlags {
 	TLF_SPRITE_VAR10      = 0x40,   ///< Resolve sprite with a specific value in variable 10.
 	TLF_PALETTE_VAR10     = 0x80,   ///< Resolve palette with a specific value in variable 10.
 
-	TLF_KNOWN_FLAGS       = 0x7F,   ///< Known flags. Any unknown set flag will disable the GRF.
+	TLF_KNOWN_FLAGS       = 0xFF,   ///< Known flags. Any unknown set flag will disable the GRF.
 
 	/** Flags which are still required after loading the GRF. */
 	TLF_DRAWING_FLAGS     = ~TLF_CUSTOM_PALETTE,