Firmwares

You can get firmare version with $342 register and get b0,b1,b2. It will show the firmware version.

There is only 2 versions availables :

Firmware 1

Firmware 2

Manage microdisc compatibility : it handes $314 register to switch on the right ram overlay bank

Firmware 3

Under development

Firmware 4

It's under development but it will handles others hardware chips.