I have a 878UV Plus with bluetooth and gps, and Not a bit of issue with it . I also have the 578UV Pro and no issues with it Or the Cps. Both radios are the original firmware. The trick with these, is NOT to update the damn firmware every time a new revision comes out, Unless it's a bug fix and is Proven to solve the issue. I've had Anytones for 6 years, and numerous Dmr radios, and everyone has issues with them, but me. Get a FIRM understanding of the Cps and anytone's software, that's the key !