if you want to send me your hitachi drive and pm to get my e-mail so you can send your orig.bin I will have alook for you if you want
once it was repaired to test it one by ejecting it with the xecuter connector and another way is to put the original fw on it and then see if it takes being flashed.
if anything wrong with the ones form HK it would be the laser but you have a spare in your old hitachi
I have a samsung comming from HK off ebay to test
but before you go spending out send me your drive £5.70 special delivery per direction, and I will have alook at it, reflash and refit the tsop.