Changes in how FCC unlock runs in ModemManager

Aleksander Morgado aleksander at
Wed Nov 10 15:09:21 UTC 2021

Hey all,


I've been complaining about the FCC unlock procedure since we first
knew about it some years ago. The sad truth is that more and more
laptops are being released these days with FCC locked modules, and
ModemManager should not forget about those users. But it is also true
that the FCC unlock procedures that we had included in ModemManager
are reverse-engineered from vendor-provided tools, and we're not
really aware of what those procedures may really be doing in addition
to the FCC unlock.

All this is changing now, with a new procedure integrated in
ModemManager which will run external programs to perform the FCC
unlock, either provided by MM itself or by third parties.

So, long story short:
 * ModemManager will no longer attempt to automatically FCC unlock
modules, unless manually configured to do so by the user.
 * We don't drop our built-in FCC unlock procedures, we move them to
example scripts under /usr/share, and require the extra manual
configuration step.
 * Vendors can now provide their own FCC unlock procedures, in a way
that can integrate nicely in the ModemManager state machine.

Please see the changes proposed here:

Comments welcome


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