Description
I recently got a SIM card for my Dell Latitude 7450 it has the Snapdragon X62 modem, which requires to be FCC unlocked after booting in order to work.
This issue is mostly for documenting what worked for me.
ModemManager currently doesn't have builtin support for this modem.
In a Dell forum post I found a link to the fii_linux project which contains the binary FoxFlss to FCC unlock this and other modems.
I was able to put the project into a derivation and "build" it, the binary is unfortunately closed source.
The derivation can be found here:
https://github.com/Nebucatnetzer/fii_linux/blob/37165c46c4bc95f0491af2ca20fc42e5e11f3640/flake.nix#L14-L29
I wasn't able to integrate it with the ModemManager option for FCC unlock scripts.
However unlocking the modem manually works so I wrote myself a little helper script:
https://github.com/Nebucatnetzer/nixos/blob/1a1cdcde9bd008691f074f2c242176771d51cdd3/systems/capricorn/default.nix#L15-L31
For Lenovo there seems to be a similar binary and there is a PR for packaging it for NixOS.
Someone there used buildFHSEnv because the Lenovo binary contains hardcoded paths.
The Foxconn binary has the same problem but petchElf worked just fine for my use cases and I don't know enough to decide what works best.
lenovo/lenovo-wwan-unlock#52