Yeah - reading the source code of QEMU I found the structure of the NVRAM -
EVEN BETTER there was a WEB page with a good description of the various NVRAMs on Sun
machines up to Ultra1. Yes, there "was".
FORTUNATELY via
archive.org, that page can be accessed - Tadaaaaaaaa- here it is:
https://web.archive.org/web/20151107014449/http://www.squirrel.com/squirrel…
HOT: As I suspected: The first byte of the hostID in some systems defines the machine
type.
PERFECT: There are also commands given to read/write the NVRAM from the firmware.
Thanks Ethan, the hint to check the emulation was great!