cannot recover from gpsdo=internal

[shimaore]

If you accidentally set the gpsdo EEPROM parameter to internal, apparently ZPU does not start the UDP services for RX/TX.
This makes all UHD-based services (including uhd_usrp_probe and the osmo-trx transceiver) fail with

Error: resolve: Service not found

What is problematic is that the current usrp_burn_mb_eeprom utilities will fail the same way, and prevents you from resetting the gspdo parameter to none. As a workaround I commented out the section under create gpsdo control objects in lib/usrp/umtrx/umtrx_impl.cpp and was able to re-set the value in the EEPROM.

It would be nice if the usrp_burn_mb_eeprom utility could be made to recover from this situation.
Alternatively, since based on ZPU's behavior, it seems UmTRX does not support gpsdo=internal, maybe preventing to set the parameter would be a simpler solution.