Toshiba 4TB 3.5" - PCB - which is ROM IC ?

[fzabkar]

@befreetech was able to get the donor PCB to work after transferring IC10 only:
https://forums.tomshardware.com/threads/x300-toshiba-firmware-identify-and-swap.3259107/

This thread contains ROM dumps (some are corrupt):
http://www.hddoracle.com/viewtopic.php?f=24&t=2712

Here is a tool which I wrote to analyse the ROM contents:

Toshiba ROM-CPs tool :
http://www.hddoracle.com/viewtopic.php?t=1724
http://www.hddoracle.com/download/file.php?id=8958

[Nick_CT]

I find that odd as I had swapped IC10 only, as I said, and drive did not intialise.

[fzabkar]

I find that odd as I had swapped IC10 only, as I said, and drive did not intialise.

A proper ROM dump would have been informative ...

[fzabkar]

The 3 additional "ROMs" appear to constitute the nonvolatile memory (Persistent Write Cache) which forms the basis for power loss data protection.

https://www.storagereview.com/toshiba_mg04sca_enterprise_hdd_review

Toshiba also offers what they call "persistent write cache technology" with the drives, which delivers gains in performance and data reliability.

Persistent Write Cache (PWC) basically means that data in the write cache that hasn’t yet been completely written to the media will “persist” in the event of a sudden power loss; this is very useful for Advanced Format drives supporting emulated 512 (512e) sectors. When a non-aligned write occurs, it may cause a “read-modify-write” operation, in which an extra rotation of the disk is needed to write the modified sector to the storage media. As such, when a power surge or loss occurs, the back EMF energy of the spindle motor is used to power the write data loss protection circuitry and is also able to power the transfer of the RMW data to NV memory. When power has been re-established, the RMW data is restored from the NV memory to the write cache and the RMW operation is completed. This functionality helps to curb any inconsistency between write data the host has transferred and write data the drive has committed to the storage media.

ISTM that care must be taken not to inherit the PWC from a donor PCB, as any cached data could be written to the patient's UA.

[fzabkar]

I find that odd as I had swapped IC10 only, as I said, and drive did not intialise.

What would happen if the donor PCB came from a drive with a larger capacity, and whose PWC contained pointers to LBAs which exceeded the capacity of the patient HDD?

[octothuluh]

I got a Toshiba X300 series, model HDETS10GCA51, capacity 6Tb, firmware version FS2A. It also has 4 ICs.

In this case, just transferring the Macronix ROM IC in IC10 location to donor board and clearing the SMART module made it work.