if you upload the source, i can add the mentioned modifications

I would change the sequence of LPT setting and video memory deletion, LPT would contain 3F left margin, after deleting video memory left margin would set to 0B, by this 52 sec problem, and dirt on the screen can be avoided if default EXOS system segment is used as video memory. The easiest way (and not 100% sure) if you check if page0 contains FC, if it is, then the machine is EP64. You do not use the extra memory, and after 52 seconds the original version would run on EP64, but after my patch it does not, it even does not use extra memory, but by changing video memory from FF to FD the game will overwrite 2nd game page by video memory, because it is loaded to FC and FD.

What do you think about the "force an immediate re­load of the line parameter base pointer" (reset b7 of 83h)? Then probably will work the original memory layout? (anyway more EXOS compatible don't ruin the FFh segment )

Good idea, i forgot about this possibility , but yes i would like toadd more exos compatibility to avoid destroying system segment(s) if possible.