If memory serves correctly at 2.1, even if you have the image files. If you dont have the program to transfer them it wont do you anygood. To add if you do have the transfer program it will not install without SCT on the same PC. Also you must be at NAE for I do not think it will work over the network. I may be wrong, but I think its locked down good.
Mac, I agree with you 100% on piracy, However, If this guy is the original purchaser of said NAE. Anything needed for its current revision for fundemental operation should be included in the deal. Or at minimum, provide the service to reimage at a discount (Time).
If you really mean a "Bios Update" for an NAE55xx, then you should contact the branch that provided the NAE.
There was a Bios update released back around the time of MSEA v1.2 and the release of MSEA v2.0. It was my understanding that the NAE update (from version 1.x to 2.0) AND the bios update (using a toold called "BiosUpdateTool" were free to all customers INCLUDING labor by the branch.
If yours never had its bios updated, I think the selling branch has done you a disservice.
If, however, your NAE was purchased after this time (if it came with v2.0 or later), then its unlikely that it needs its bios updated.
If you are actually looking for an UPGRADE (say, to v3.1) then you'll have to pay for it.