In the ex-Soviet countries are very popular machines the different clones of the ZX Spectrum. And exist a many machine which are not only simple clone: more memory, integrated floppy controller, sometimes new graphics modes, turbo mode, etc...
I think the most popular advanced version are the Pentagon and Scorpion machines. And many new game writed for these machines, which are use a more HW resources than the original Spectrum games.

I think it is great idea convert some of these games to the Enterprise

But hard to find programing informations about these machines
Anyone expert in programing on these machines? Or can help to dig out informations from the "Cyrillic internet"?

*port 7ffd. full compatibility with Zx spectrum 128. digits are:
 
D0-D2 - number of RAM page to put in C000-FFFF
D3    - switch of address for RAM of screen. 0 - 4000, 1 - c000

On original Spectrum 128 this is the screen selection: D3=0: RAM5, D3=1: RAM7 (and RAM7 can be accessed by the Z80 when it is paged to C000-FFFF).
On the russian clones any other RAM segment can be works as video memory, if it is paged to C000-FFFF?