Pixhawk Won't Boot after Changing ISBD_CONFIG

Hi all,

I am setting up a RockBlock Iridium device with my Holybro Pixhawk 4 (daily release QGC and latest stable release PX4). When I try to select TELEM2 (or any other port) for the satellite module using the ISBD_CONFIG parameter, save, and reboot, the Pixhawk doesn’t boot. It beeps the SOS signal and doesn’t connect to QGC. The ONLY way to revive the board is to flash Ardupilot and then flash PX4. Reflashing PX4 directly does not work. I’m not sure why this happens; I am doing exactly what the docs say.
I would like to add that the iridiumsbd driver will not start no matter what I try in the MAVLink console.

Any help would be greatly appreciated.