I am having the same problem with V6.83. It works fine on the first flight after a configuration/firmware update, but on subsequent flights I start getting the 'own ship' alarm. What appears to be happening is that the configuration is getting cleared on these subsequent flights between power cycles. I discovered this because I can read the configuration file through my S80 vario and the ICAO was FFFFFF. Not only does the S80 allow you to view it, it allows you to change it. So I tried entering it (while airborne) and the PowerFlarm wouldn't accept the entry - bummer. (If there is a way to change the FLARM settings from the LXNAV products (while airborne), someone enlighten me if it is operator error).

To work around this problem, I now leave a thumb drive in the cockpit with the Powerflarm config file. When I power on before each flight, I make sure that I insert the thumb drive first so the config file gets loaded each time. You can also do this airborne if you happen to forget to do it pre-flight - which is easy to do because the own ship alarm won't get annunciated until airborne. Unfortunately, you will have to power cycle the FLARM which will mess up your IGC recording once airborne.