I can understand the OP's issue.

A copy of the modules/ROM in SA is useless if you can not acces the SA (physical damage, failure, etc.)

Fortunately, the ROYL architecture is smart designed enough to reconstructe the ROM, or at least, to know the basic properties of the disk drive in question. Do pre-ROYL or Caviar hard drives can be inspected through the ROM dump to at least know the serial number of the drive? (no, no way of copying from SA when it is damaged)

Thank you in advance.

This is not true.

MRT/PC-3000 can access SA even without the original ROM (provided the head block is functional)

Mmmmm. Even if the platters are scratched, broken, etc?

I mean, let's forget the ROM in the equation. How do you read an SA that is damaged ? (I mean real damaged).

And if (just wondering, not sure if this could even work) the head block is functional, and the read is posible only for the UA, (not the SA, for example, for damaged surface).

Do only-software tools like WDMarvel could be used to read the UA as RAW data or Track data (as much as possible), and then could be tried to reconstruct with some form of C, C++, or even VB programming, searching for File-Allocation-Table (FAT) signatures in the RAW or Track data recovered?

Just an idea, not sure if this could work in practice.

Thank you in advance.

Without access to SA, at least to certain unique modules, you will not have access to UA by LBA in any way.

If you somehow managed to read through PBA / CHS, in most cases what you would have would be a pile of junk. I don't think it's a viable system for data recovery.