Help? Killed my DW-U54A Firmware

HI,

I have a Sony DW-U54A drive I installed in a GRX560 laptop. I screwed up the drive by flashing from firmware 1.0b, to 1.5a. It will no longer burn DVD’s and gives an illegal disc, and a cannot end disc at once error…
I got the firmware for RPC1 flashing and it appeared to do fine and Nero saw it as having new firmware.
Is there a source to get the 1.0b file, it worked fine with all media then, now no media works. Also I thought I read a thread somewhere saying that this drive might be flashed to a Lite On firmware, with cross patching??
Any help would be appreciated…