Yes, it is possible. If I were you, I'd find a close matched donor with the same FW revision (or even two or three) and compare the NVRAMs of them all. There are only certain segments of the NVRAM that are actually unique to each drive. You might find that a few bits have been flipped and thrown off a few values that are necessary code that isn't drive specific.
Also, you might want to try putting those NVRAM codes into another ROM of the same firmware. It's possible that it's other code in the ROM that's corrupt besides just the NVRAM code.