PS4 HDD, NOR and Syscon Backups Console Restore?

[engineer]

Hi,

I have a backup of the HDD, NOR (sflash) and syscon chip from a fat PS4 with FW 8.50/8.03 (Active/Inactive).

Case #1
Say I update to 10.0 (USB). So now I'm at 10.00/8.50 (Active/Inactive).

I am aware that I can revert (old or newer revert method) to FW 8.50. Then, I would have the option to update to any FW >= 8.50. Or, stay at 8.50.

What I'd like to know is, if I choose to not revert, but rather write back the 8.50/8.03 back-ups (HDD, NOR, and syscon chips). Would that essentially undo the 10.0 FW update, and restore everything to the initial state of FW 8.50/8.03?

Case #2
Say I update the now 10.00/8.50 (Active/Inactive) PS4 to 11.00 (online). So now the PS4 is 11.00/10.00 (Active/Inactive). Would writing back the 8.50/8.03 back-ups (HDD, NOR, and syscon chips) undo the 10.0 and 11.0 FW updates, and restore everything to the initial state of FW 8.50/8.03?

Simply put, with a matching trio of backups of HDD, NOR and syscon, would writing (back to the PS4) any of these trio of back-ups from past date x, restore the PS4 to this back-up FW state from past date x? Or, are there other locations/efuses that would limit us to only switch back to either of the two latest (on-console) active/inactive FW states?

CUH 1001A, SOP16 NOR (MX25L25635FMI-10G), and 100-pin (R5F100PLAFB) syscon IC. All original components.

Cheers

 

[PSXHAX]

If you haven't yet, try reaching out to @BwE on Twitter about these questions.. he hasn't been on the forum for a few years, but would likely know the answers as console repairs are part of his profession.

If anyone else can lend a hand feel free to jump in, and the psdev wiki also contains loads of information if you have the time to research it all of course.

 

[Kendek]

Fortunately, there are no eFuses, so Case #2 also works without any issues.

 

[engineer]

To answer my own question, yes you can.

I have a fat 8.50/8.03 (active/inactive) unit which I backed-up all three of syscon, sflash (NOR) and HDD (I'll refer to them as the trio). Then I updated (USB) this PS4 to FW 9.00/8.50. Power-cycled and all. Then I took a back-up of the 9.00/8.50 trio. Then I wrote back the 8.50/8.03 back-ups to the trio. PS4 booted fine and all. Did an online FW update to 11.02/8.50. Power-cycled, synced with PSN, etc... Then I took a back-up of the 11.02/8.50 trio. Then I wrote back the 9.00/8.50 trio. Again booted and everything is fine. Then I wrote back the 8.50/8.03 trio. Again everything is fine. Then I wrote back the 11.02/8.50 trio back, and again everything is fine.

In short, as long as you have matching FW back-ups of all three of syscon, sflash (NOR) and HDD, you can switch back and forth to any FW you have a back-up of.

I didn't need to change/modify any addresses in any of the binary images.

Cheers.