The chips arrived.

Looks good!
If my memory test will detect as CMOS Z80 then these are not fakes. The 1992 date code looks good. Chinese fakes have few years old date code.

Definitively the two chips are CMOS, but I still have to weld some components.

EXOS have a ROM equality check.

I extract from old videocard this chip.
It can be useful for installing into cartridge (I have 1 free socket) or into EP?
I'm not very good in hardware.

Thanks.

I wanted to know if that chip can be programmable and it electrically compatible.
Now I understand.

Found only that specs

http://www.radioradar.net/files/preview_images/datasheets/157258-2.png

http://www.radioradar.net/datasheet_search/A/2/7/A276308A-70_AMICTechnology.pdf.html

but I have something similar chip which is Winbond 27EE... compatible, these are electricaly eraseable EPROMs.

Found it, It is a another thing: ASD AE27E256

And I also have a AMIC A276308A, and yes it is OTP. My one empty at the first half (32K), this can be used for EP, just need Pin 1 connected to GND

64Kb EPROM is only usable for the internal EXOS 2.4 hack or for a 1 socket cartridge, but not for a two sockets cartridge, as the total  addressable memory is only 64Kb and supposedly you have 16KB already occupied by the Basic ROM.

For a two socket cartridge possible solutions: use only partialy the 64K EPROM.
Or hack the cartridge: connect directly the CART signal to EPROM CE (and also the required address lines), and use only one socket. Or done this for both socket, and put a switch for EPROM selection.