After further investigation, it looks to me as though conmux may have changed it's behaviour. Previously, we used to get the message <<<PAYLOAD LOST ... retrying in 30 secs>>> (the time could be variable) and we would eventually retry and connect. My feeling at this stage is that the retry isn't happening.
If I just run 'sg dialout "cu -l /dev/USBsnowball01 -s 115200"' after stopping the conmux daemon for that board, we just get a disconnect after power is removed. If I reconnect power and then restart the dial out, it connects properly.
After further investigation, it looks to me as though conmux may have changed it's behaviour. Previously, we used to get the message <<<PAYLOAD LOST ... retrying in 30 secs>>> (the time could be variable) and we would eventually retry and connect. My feeling at this stage is that the retry isn't happening.
If I just run 'sg dialout "cu -l /dev/USBsnowball01 -s 115200"' after stopping the conmux daemon for that board, we just get a disconnect after power is removed. If I reconnect power and then restart the dial out, it connects properly.