What to transplant between PCBs?

[sonjadisk]

Dear all,

I am working with a Seagate Momentus 5400.3 160GB (model no. ST9160821AS).
Attached you will find an image of the original PCB (left) and the replacement (right)

Since there is no obvious ROM IC to transplant from the original PCB, should I just transplant the entire controller IC? Also, should I leave the 8-pin chip that's on the replacement but not on the original PCB there or should I desolder it?

Any input will be appreciated, thanks for reading!

sonja

[BGman]

Don't you see that MCU's are different?
Just find another donor.