How to unlock Eberspacher auxiliary heater in California T6.1?

[Toeter Nitoe2500]

Can anybody tell me how to unlock my auxiliary heater (Eberspacher in VW California T6.1 MY2022)? Some background; I was camping at an altitude of 3750 m in Ecuador. Turned on the heater on continuous mode. Worked fine for about 30', then swithched itself off. When I noticed the heating was off, I switched it on again and worked fine for 15' to 30'. After repeating this several times, I couldn't start the heating anymore, not in immediate, not in continuous mode. After some internet research and reading out the fault codes with an obdeleven I learned that the Eberbacher only works up to 3000 m. If you want to use it above 3000 m you have to install a special feature that reduces the fuel injection to compensate for the lower air pressure. According to the fault codes mine went into overheating after 10 to 30' and after 10 times, the heater goes into lock mode.
I tried to unlock by removing the aux heater fuse for 5 seconds within the first 20 seconds of starting the heater (according to the Eberbacher manual), that didn't work. Trying to remove the error code with the obdeleven app didn't work, using the "unlock heater" in the obdeleven doesn't work.
Help...

Lucas alias toteternitoe