GTC505 Firmware Update Procedure
NOTE: this procedure applies to units with S/N:23121501 and above only. 1- Connect the GTC505 to a computer’s USB port, using the supplied micro-USB cable.2- Upon detecting the USB connection, the GTC505 should show the charging screen.3- Press the “POWER/CLEAR” button until the unit turns off.4- Press and hold the “HOLD” button, and while the …