Actually the "unknowns" on vanilla maps are something completely different, not related to tile attributes. These are special values defined on the map itself (special value tells which building or unit should spawn on that tile when the map starts). But tile attributes are tied to tileset and are defined in TILEATRx.BIN tiles.
Well, maybe. I don't know. We can only speculate.
Apologies for not getting back here sooner. I downloaded 1.57ddh and installed it in my game prolly soon after it was created and on this site for DL. But I never got around to playing the game again until just recently. Everything seems to work fine, by that I mean the game plays just fine as this updated version. I don't play scenarios often enough that require a good usage of ports, but it is nice to know I have the update when I may need it. Thanks again to all.
That's even more options I though of (and more complicated too), but it really shows lot of stuff that anybody's ideas can think of.
It should be needed to do some intense testing in game not just to try all this, but to see if the game works as intended, not just crashes but all the stuff that already happen in the game.
Question; This has something to do with the "unknows" that can be seen on the vanilla maps? maybe westwood didn't full implement the attributes, but they were already programing the map to use some of them.