Help needed for devel/android-tools

Hello,

The port devel/android-tools is in version 31.0.3, but to install
GrapheneOS a recent version is needed, and I tried to update it to
35.0.2.

My diff to upgrade this port (with `git am') is available at
https://people.freebsd.org/~thierry/devel_android-tools.diff

It builds fine, but unfortunately many patches and a new file for
core/fastboot/usb_freebsd.cpp are required, and this is not my area of
expertise: something is wrong!

Any help is welcome: you don’t have to flash a device, just try

# fastboot getvar product

and it should list your connected device, but ATM it only displays

< waiting for any device >

Thanks for your suggestions.
-- 
Th. Thomas.