| Check in software and tell me if the SENDING PRELOADER command is running even you don't power on the phone, if it is the case try to swith RX and TX of your cable and check the GND wire is well solded.
USe this pinouts:
keyboard UP
_____
/12345\
_______
1: GND
3: RX (cable pin3)
4: TX (cable pin2) |