I have a test rig including a 6HC mainboard and several 3HC extensions. I has worked for many months without problem. I had to replace the pi and now there is a problem with the 6HC syncing with the 3HC extensions. The 6HC mainboard works ok on its own. Can you help?
Also, I've got an error whilst trying to upgrade the firmware. I get this message 
Can you help with this too??