TreeBeard The phone seems to think that it is in airplane mode even though it is not.
My hunch -- without looking for and reading the relevant code -- is that the situation is:
- The cellular modem isn't coming on,
- Some piece of high-level code is noticing that the cellular modem is off and is politely reminding you of the typical reason for the cellular modem to be off.
TreeBeard Is there a way to disable airplane mode at the BIOS level?
The situation isn't really the same as a PC which can be booted into a BIOS configuration program which can mark certain devices as enabled or disabled. Though I am not an expert, I am not aware of a setting/option that controls power to the cellular modem that operates before the OS boots.
If you (after backing up your data) flash the device back to Google's OS, and it is still the case that no SIM card works, that would be consistent with a hardware problem.