HELP!! USB0 disappeared from Domoticz

[Dave21w]

OK i'll make this quick as at present I'm in a bit of a panick !!

RPI3 run Domoticz 4.9700 and RFXCOM, just starting to play with MQTT so to be safe I setup a RPI2 with Domoticz and Mosquitto (different IP) so i wouldn't inadvertantly break anything on my running system. Decided that I should probably update my running system anyway as you are supposed to keep it updated, right!!
SSH in and ran sudo apt-get update, once completed ran sudo apt-get upgrade, all installed fine no errors, then domoticz started saying it couldn't communicate with the RFXCOM, rebooted system - no change.
Checked setup/hardware in Domoticz, decided to change the RFXCOM setting from dev/ttyUSB0 to dev/serial1 the idea being to change it back again after to see if flipping the port type would make a difference only to find dev/ttyUSB0 has now vanished and cannot be selected

SSH into pi with command lsusb and it lists a device connected with an FTDI chip in it, I know this is the RFXCOM as if I unplug it it dissappears from the list if you run lsusb again so as far as I can tell the usb etc is working OK, just not visible in Domoticz.

Does anyone have any ideas regarding this as I'm running out of time tonight

Thanks

[bewo]

Is there more than one device plugged to USB?

I guess the RFXcom ist connected to an other number. So i would prefer a name instead the number. Here is the way:
https://www.domoticz.com/wiki/PersistentUSBDevices

[Dave21w]

No, only the RFXCOM

Err actually yes come to think of it, my Pi only starts up from the SD card, everthing else runs from a 32GB SSD via USB, this bit obviously works as it wouldn't boot otherwise.

Here is what i see:-