The generator is switched on or off in the parameters, but not in the running system

Stops itRangefinder, optical flow, camera, OSD and other devices

What ArduPilot says:

Generator: No serial port found
Generator disabled, reboot required
No backend driver

These follow “Generator:”. A generator or fuel cell is set with GEN_TYPE, read once at boot. “No backend driver”: GEN_TYPE is not 0, but no driver was started. “Generator disabled, reboot required”: GEN_TYPE was set to 0 while a driver is still running. “Generator: No serial port found”: the fuel-cell driver started, but no serial port is set to the generator protocol.

What to do, most likely first

GEN_TYPE was changed and the flight controller has not been rebooted.
FixReboot.
No generator is fitted: GEN_TYPE came from another aircraft's file.
FixSet GEN_TYPE to 0 and reboot.
The generator's serial port is not set up.
FixSet SERIALn_PROTOCOL to 30 (Generator) on the port the generator is wired to, with its baud rate, and reboot.
This firmware has no driver for that generator type.
CheckThe Firmware Inspector lists what a firmware file was built with.
FixBuild a firmware with the generator driver.

Parameters to look at

Parameter	What it is
`GEN_TYPE`	Generator type
`GEN_OPTIONS`	Generator Options
`SERIAL1_PROTOCOL`	Telem1 protocol selection
`SERIAL2_PROTOCOL`	Telemetry 2 protocol selection
`SERIAL3_PROTOCOL`	Serial 3 (GPS) protocol selection
`SERIAL4_PROTOCOL`	Serial4 protocol selection
`SERIAL5_PROTOCOL`	Serial5 protocol selection

Where to do it:Firmware Inspector Firmware Builder Board & Wiring Planner

The code that sends it

Generator: No serial port found

libraries/AP_Generator/AP_Generator_IE_FuelCell.cpp AP_Generator_IE_FuelCell::init() · Open in ArduPilot Copter-4.7.1

Generator disabled, reboot required

libraries/AP_Generator/AP_Generator.cpp AP_Generator::pre_arm_check() · Open in ArduPilot Copter-4.7.1

No backend driver

libraries/AP_Generator/AP_Generator.cpp AP_Generator::pre_arm_check() · Open in ArduPilot Copter-4.7.1