Re: will "orig47" Do?
It's not essential to have your 'own' hitachi original firmware in order to upgrade or reflash any firmware to it. As long as it is the correct rom version, then you are good to go, the key sector of the drive firmware is untouched during the restore/flash process, this is why a generic original firmware use is possible.
What is essential is that you 'restore' to original firmware before you flash hacked firmware to the drive. Hitachi's are flashed in a 'live' state using windows api, what this means is that you are flashing it whilst the drive is present and detected in windows as a hardware device, this is unlike any other 360 drive and is potentially more risky as a result.
The need to restore to stock before flashing hacked firmware has always been the case with hitachi drives, this is not because you are upgrading to LT or whatever, it has to be done regardless.
Jungleflasher has been coded to be the safest method for flashing hitachi's, for one, it won't allow you to flash ixtreme over ixtreme (it forces restore and reminds you of such via popup) and it also has a flash stability test as part of the flashing process, this involves flashing one singular sector to the drive and doing a read-back and compare, if there is any error or a chance of bad flash, jungleflasher aborts! Hundreds if not thousands of hitachi's have been saved from brick as a result I bet (via, hitachi and winapi are not friendly with each other for alot of people, remove drivers for via card and use portio option for restore/flash)
If you download the ixtreme v1.51 for hitachi pack, you get it all, all hacked firmware for all rom versions and all original firmware for all drives too, so you can restore then flash from the one pack. I would also add that hitachi drives handle the video partition a little differently to all other 360 drives, so at this point in time iXtreme v1.51 for hitachi boots all 360 games, regardless of wave (4,5,6 etc)
Hope that explains a little what you needed to know, I apologize for the post length but it was necessary!