I'm coming from standard Oxygen OS 11.
There are firmware misplacement, the firmware files are set a directory up, and aren't found by the kernel. Even when the position is adjusted, the kernel still can't find them (the kernel gives error -2 even when the firmwares are everywhere, in the usr/lib/firmware, in the lib/firmware in the right path, EVEN in the INITRAMFS). I thought it could be because the ADSP drivers are embedded in the kernel, so the driver search's for its firmware before the file system is properly mounted, but that doesn't seem the case (the errors occour after the third second). The kernel still can't find the firmwares in the majority of the times, but when it's found, it still can't be inizialized, as the error -22 shows up
There are SIM / WIFI / BLUETOOTH issues, Mainly caused by the co-processor ADSP not booting.

Adjusting the firmware position on the main file system doesn't resolve
Substituting the symlinks of the firmware files with the original files doesn't resolve
Manually modifying the initramfs doesn't work (and I've had problem with UEFI/GRUB, wich seems a lot different from a normal kali)
echo start | sudo tee /sys/class/remoteproc/remoteproc0/state gives -EINVAL (so maybe the driver is built-in in a crashed state)
Trying to flash rootfs image of 2026.1 with the new 2026.2 boot image obviusly didn't work (I just tried, you know, it takes nothing to try)

BUT...
Every USB problem has been solved, the only thing I had a bit of trouble with was ethernet / USB routing.

SUGGESTED SOLUTION:
Embed the firmwares of the ADSP in the kernel itself.m