I notice that Dr. Schäfer has been dumping COP421 mask ROMs and uploading the data to bitsavers.
http://john.ccac.rwth-aachen.de:8000/patrick/COPSreader.htm
As far as I know, the mask ROMs in the COP421s were basically the last bit of code in the Lisa's hardware that hadn't been preserved on modern media. Thank goodness it won't be necessary to work out the ROM contents from the
die images on visual6502.org!
Fantastic work! Patrick, if you are reading this, where can I subscribe to your newsletter?
--Tom