You got to connect your E3 Flasher with the Nor tristate. So solder a wire from Nor Tristate on motherboard to the orange wire SBE.
PS: Only use this image to check where the Nor tristate is, do not cut anything like written
Once it is done, put all key down on E3 Flasher but first key up. So you only put up the 'Flash Fun Mode'. Now turn on the PS3, it shouldn't do anything but if you succeeded, the console is gonna stay on. Since the PS3 stay on, you're able to flash back your dump bkpps3.bin. That should unbrick it and let you follow the tutorial again.
PS: Make sure you use Rogero 3.55 V3.7A firmware for downgrade and the JaicraB's Patched LV2Diag.self to downgrade