hi ive got the same problem on one of my later gt3b,gt3c and earlier gt3b are fine,when you do a button check its like the bind button has been deleted. I flashed mine with psx and an STLink V2 lost bind function on later version,reflashed with original firmware and still no bind!!!! now have one of my later gt3b dead in the water literally as its for one of my boats. Anybody out there got a patch for this problem.