There might be solution to the keyboard disconnect issue here… It mentions “other bugfixes from current firmware related to i2c and such”:
Though it appears to only be available as a binary, with no link to sources (yet). I found another updated keyboard firmware, with sources, that I mention below that post with links, but it only added features and didn’t seem to have any bugfixes.
Perhaps the problem wasn’t in changes to PicoMite, but was something to do with the keybaord firmware all along? I’ll test this out when I get a chance. Though since the problem is hard to reproduce, it might help if others try it too.