Thanks. I received a link to an image to directly install 23.01 on the two SG-1100s. I did one last Friday, worked fine. I plan to do the second one shortly. These were not in production so there was no useful configuration to back up before the online update attempts bricked them.
Once they are both working, I plan to use them to become familiar with new features of 23.01 while I wait for clear stability before upgrading the SG-3100 that is a production device.
Best wishes,
Ken