My friend just bricked his PS3. I downgraded his PS3 about 3months with Rogero v3.1 and he wanted 4 days ago to install Rebug firmware to connect to PSN. Of course i told him not to change the firmware, but he did (he wanted to install OFW 3.55 and Rebug..).
And the result - YLOD. After 2 days of experiments and reading all internet i failed to boot PS3 without PA0 nor tristate solder. PS3 boots normal with PA0 nor tristate solder but without it result - black screen. Today morning i made an experiment (unbelivebable simple) and PS3 booted without soldered PA0 nor tristate to E3 flasher.
After that i did the normal downgrade to ROGERO CFW 3.1 !!!
P.S.: I had only his 4.0 backup (he told me after i did it ) and he bricked his PS3 on installing OFW 3.55 !!! I am from Moldova and i will tell you how to unbrick PS3, only if you have a nor backup. With this method you can unbrick multiple PS3 with one E3 flasher only if you have a nor dump extracted before !!!