They may be compelled to release any driver code associated, however firmware is not covered by relation to kernel. Linux runs on mostly proprietary firmware. The “linux-firmware” package in many distributions that contains hot plug firmware is mostly proprietary blobs.
That said I doubt they had much significant firmware work, it may just be logo and some tweaked configuration from their SoC vendor. They likely had to modify AOSP a bit more to allow their launcher unfettered access to the device in ways not modeled by standard AOSP, but that’s user space that isn’t GPL.
They may be compelled to release any driver code associated, however firmware is not covered by relation to kernel. Linux runs on mostly proprietary firmware. The “linux-firmware” package in many distributions that contains hot plug firmware is mostly proprietary blobs.
That said I doubt they had much significant firmware work, it may just be logo and some tweaked configuration from their SoC vendor. They likely had to modify AOSP a bit more to allow their launcher unfettered access to the device in ways not modeled by standard AOSP, but that’s user space that isn’t GPL.