Olivetti M10 ROM patch
The Olivetti M10 isn't compatible with REX or any M100 Option ROMs. However the hardware is nearly identical, except for the keyboard. To address this, the Model 100 main ROM was patched to work (reasonably well) in the M10.
Use the patched M100 Main ROM in M10 by burning a 27C256 eprom and mounting it in the M10. Files are located here: