I build an experimental bios version 1.5 based on the official 1.4 version.
There are only a few changes:
- LCD backlight is done using multiples of 16
- KBD backlight is done using multiples of 32
- Register 0x01 returns the version number
My current PicoCalc specific PicoMite versions can display the BIOS version with variable MM.INFO(BIOS).
The BIOS and source can be found at http://raspi1.mypi.co/download