Aren't we looking at two problems here?
One: The U/S Radio, which if not removed, could probably allow the A/C to continue flying albeit with some restrictions till repaired. Either an MEL or AFM Sup might help?
Two: Removing the U/S Radio. If it's removed, you've effectively now modified the A/C which will render it grounded, unless you get an approval (Engineering Order).
Is it possible for you to fly the A/C to facility capable of repairing the defect?