@owd200 But you're restarting to recovery... in the first screen you see "recovery mode", use vol keys to switch it to the fastboot option. In theory, it should land again in the same screen after restart and fastboot should recognize the device in your PC

I faced this in the past. The steps I made for get back fastboot was:

• Turned off the device (battery out 10 secs)
• With the phone off, volume down + plug in USB
• IN THAT MOMENT you'll see fastboot but it won't be detected, you need to select in the fastboot options to restart (again) into fastboot mode.
• Once it restarts, you should be able to detect the device with "fastboot" command and be able to reinstall ubuntu (what I did using the UT installer tool) or reflash android