I've sent a PR that adds the rest of the ROM revisions to the Olivetti M24 driver.
The emulated M24 somehow gained a second, faulty RT clock ... why does the BIOS even detect two RT clocks?
A real M24 is content with having one RT clock ...
The ROMs of the badge engineered incarnations of the M24, the AT&T PC 6300, the Xerox 6060 and the Logabax Persona 1600 are identical to the M24, retaining the Olivetti string in the ROM.
Is there a way to add an alias to access the M24 driver under another name without duplicating the ROM section? If so, I'd suggest to add at least a pc6300 alias to make the driver more familiar to US users.