Nope. Same Exact Software on all versions of 4.45.. it's sorta like this (one possibility):
All but 2 80GB drives, all but 3 160GB drives, and all but 5 320GB drives have [TechnicalPartChipTypeA] as a part of them.
1 80GB drive, 2 160GB drives, 3 320GB drives, and All but 2 500GB Drives have [TechnicalPartChipTypeB] as a part of them.
1 80GB drive, 1 160GB drives, 2 320GB drives, 2 500GB drives, and All Larger Drives have [TechnicalPartChipTypeC] as a part of them.
Firmware 4.45 Can Identify TechnicalPartChipTypeA and TechnicalPartChipTypeB so it loads and runs fine.
Firmware 4.45 Cannot Identify TechnicalPartChipTypeC, so people with that part in their Hard Drives have the firmware not recognize the hard drive, keeps trying to identify it, sits on the swirly screen, and Bricks.
It's a driver thing.... it's why almost everyone with 1TB drives bricked, many 750GB drives did, a few 640s, 500s, and even a few 80s, 160s, and 250s did.. It's a part in the manufacture of those specific drives that are in bricked systems.. It's not a defective part, it's not a broken part...
..it's simply a compatibility issue between 4.45 and the specific hard drive in the system.
How do you fix this?
Make a 4.46 firmware that can identify everything 4.45 cannot.
...but first, Sony Engineers have to figure out what that common "unidentifiable" part is.. whether it's a chip on the drives, a certain pattern in their make, whatever.. once they figure that out, they can fix it.