Background: Friend plugged wrong power supply into his Maxtor USB drive (Barracuda 7200.10 320GB) and disk stopped working. The area marked in red (see disk on left of picture attached) is scorched. Disk not spinning up. Need to get data off the disk.

What I've tried: Found exact matching disk (on right of picture), part, firmware etc and swapped in PCB to old disk. Disk now spins up but is not recognised in BIOS (New disk is recognised when I try it)

What should I try next?

a) Swap ROM chip? I know someone who can solder chips so if this is the next thing to try is it a case of removing both ROM chips and soldering on the old ROM to the new PCB? I think the ROM chips are the ones I've circled in the picture (have something like 25PO5VP on them). Is this correct?

b) Is there anything else I should try first?

c) Are there any guides to swapping the ROMs?

Any advice would be much appreciated. Oh, if this all does works and I do get the data off, I take it I could put the new ROM chip back on its original position and use the new disk (or is that risky?)

Yes HDD startup even u should get readiness at ATA registers, but doesnt complete the full process " answer to the read sector command " , because the Microcode inside Donnor ROM , dosnt match with overlay´s on SA because u were using Donnor PCB , the next step its solder the Serial ROM, that could be accomplishied by experience there are not manual to did that if u dont have the experience send to a proof DR people

Regards