whats the state now? after flashing that dump? is it booting to xmb? with no e3leds or just not booting at all
maibe cuse of the bytereversed dump it can't read it properly and thus e3 not working?
if u havea clean working dump! then if postive e3 is 100% connected tight, erase/restore the bios(all switch down or flashfun > 1UP/2,6DOWN if not booting with that good dump(FI.I header!) just in case check with Hxd
that dump u flashed is software dump? run those dumps true flowrebuilder and choose byte reverse dump, dump is E3 ready then
proceed with downgrade