Index: src/industry_map.h
===================================================================
--- src/industry_map.h (revision 27170)
+++ src/industry_map.h (working copy)
@@ -280,7 +280,7 @@
static inline void MakeIndustry(TileIndex t, IndustryID index, IndustryGfx gfx, uint8 random, WaterClass wc)
{
SetTileType(t, MP_INDUSTRY);
- _m[t].m1 = 0;
+ _m[t].m1 &= 1<<4; // Make sure bit 4 is unaffected.
_m[t].m2 = index;
SetIndustryRandomBits(t, random); // m3
_m[t].m4 = 0;