i accidentally erased the firmware on this drive. i could not find the firmware online. anybody can help recovering the firmware?

How did you manage to ERASE THE FIRMWARE (moreover : ACCIDENTALLY) ?

In any case if you destroyed ROM maybe "something" is possible (but not what you think i.e. brutally copy another ROM : this is exactly why simply swapping a PCB won't work).
If you erased completely the FW part on the platters, forget data.
An attempt is possible with 60-70% (rebuilding all) but it's gonna cost you a lot of money and there's no implicit guarantee about getting all data back.
Finally I can make the drive work again (rebuild all , will destroy everything on drive) but you have to send me the drive so it's not convenient.

What?

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You don't have to backup all of your files, just the ones you want to keep.

LOL... i was actually messing with firmware on another device while i had the drive connected to my pc, and accidentally switched the port to the one where the drive was. Maybe it wasnt a smart idea to decide to play with firmwares after 16 hrs of work and no sleep for 36hrs

Ehm... no.

Now you have 3 options :

- Pay a lot of ca$h (not a lot, a BIG lot) to have the drive fixed and data back (and it's not sure it will be possible).
- Write a fresh FW and use the factory procedures to "fix" the drive and use it again, but forget data.
- Use the drive as spare parts.