Lenovo T99W175 / Foxconn SDX55 update on LVFS breaks FCC unlock

[Aleksander Morgado]

Hey!

> Lenovo just published a new firmware for the T99W175 / Foxconn SDX55
> 5G modem on LVFS [1] that effectively soft-bricks the modem under
> Linux as the FCC unlock no longer works.
>

Thanks for the heads up! I personally will keep my module with the old firmware.

> I can boot up Windows and downgrade the firmware, but would be
> interested in a more permanent fix.
>
> What would be needed to figure out the new unlock procedure? Any hints
> are much appreciated!
>

Lenovo published already their own FCC unlock tool here
https://snapcraft.io/lenovo-wwan-dpr
Haven't tried it yet here though, I'm still using the old SDX55 firmware.

If you don't want to use that closed source tool and If you're
interested in reverse engineering the process, looking at what that
tool does would be useful I guess.

-- 
Aleksander
https://aleksander.es