I was not able to repeat the problem on any other 433AH boards that I had. I tested 4 other boards, one with a very similar serial number. I even restored a backup from the suspect board and the other board upgraded fine from 2.20, but here is the info from the suspect board.we will try to find some similar aged boards. Please write with the serial number (or mac address) for board so that we can find one made around the same time and test.