DEX PS3 4.81 Updated to 4.82 OFW with Black screen

hello, i received my friends ps3 which is bricked i can say. The ps3 is SLIM with 4.81 rebug DEX Converted, it was then updated to 4.82 OFW and the ps3 now is in update loop,it boots only with its own HDD, with an another HDD or without stays in black screen unresponsive, nor enters recover mode. i have E3 Flasher, and i can make a dump and give it to anyone who can help me recover from this brick,i dont have a FSM Dongle nor the original dump(CEX), thanks for reading
EDIT:
ps3 shut downs...

DEX PS3 4.81 Updated to 4.82 OFW with Black screen