I'm confused

I understand that in the end he used the bad hdd with the donor's PCB and the firmware extracted from old hdd and flashed with WDR. So..what adaptive data you say there...the firmware has all what it needs on SA, because it's the old firmware. There it's no conflict between ROM->SA mdules, they match. I assume that WDR write bogus data, perhaps not the entire 192kb block...and the firmware get stacked somewhere during boot.

So the VSC commands which in my opinion are processed by the firmware (the status VSC command...has some version numbers..which make me believe that it's part of the ROM frm)...won't work..so no more flashing via WDR.

Then why he used the chip programmer? I assume he didn't had any pleasure in un-soldering..instead using 2 clicks WDR on the new PCB with HSA disconnected. What would you try first
The old bios was incompatible with the new board...who knows..other ports mapped in other ways which the old bios couldn't access...other addresses on new PCB.
If it spins..it's not a sign that works..maybe the firmware worked fine until spinning the plates but crashed few functions after. Some functions inside the firmware were ok executed while others no...because the hardware differs from the what software "knows".

In other way..I assume that the kernel loader (the first code executed from the bios...first table entry in bios.bin) try to check the ROM modules against the SA backed up ones..and if it cant read or read bogus data..then it display WDC ROM. The ROM flash..has only the basic data to access the SA. How many heads are..etc. From what I've read the SA is written especially in the middle of the platters (or around there) where the heads don't need adaptive data to read the info.

The hdd identifies with WDC DISK or WDC ROM in model field .DISK indicates it was already loaded from disk. More, lets assume that the SA modules are bad...in this case we should have access reading each head. If we get errors on each head..it means that the Preamp is dead.

that soic8 stuff is awesome. It prevents me destroying the PCB

the MCU must match 100%. I believe that.."almost" doesn't work here. I have little experience with some PIC programming, but I know that on a cip..a pin must mean something, while on other..it will do something else. It doesn't involve opcodes..which is the language..but the hardware locations where the software try to communicate with the MCU.

Hi again,
I tested new PCB with old drive and old ROM with connected and without connected head stack.
Unfortunately, I don't have got that SO8-clip, I had to unsolder the ROM, solder some wire on it and put it in the programmer.
Old drive with new PCB and old ROM wasn't able to connect via WDR, too.

Old drive with new PCB and old ROM wasn't able to connect to WDR and doesn't either spin up. With insulated HSA it spins up but stops shortly after that and WDR wasn't able to connect.
I think it was a kind of luck, WDR was able to read ROM from old drive with old PCB.
Is WDR able to connect to HDD instead PC-BIOS isn't able to recognize HDD? My PC wasn't able to boot with connected HDD, so I connected it during running Windows.
I tried any possible combination of drive and PCB, with and without insulated HSA. But WDR couldn't connect to PCB.
Should WDR be able to connect to PCB without any drive? In my case, it wasn't. Either with old PCB and old ROM or new PCB with its own ROM or new PCB and old ROM.
As I understand, MCU loads firmware and adaptive information from ROM? So MCU loads firmware through a bootloader via SPI from ROM?
If it works that way, I don't understand why drive won't spin up with connected heads. Maybe because of different assembly and therefore different voltage etc. for HSA (already mentioned by Nebojsa_28) or damaged driver in HSA (mentioned by Spildit). But nevertheless, old drive spins up and does some clicking with old PCB and old ROM.
Should I try another PC with WDR to connect to HDD (as I mentioned, I've got an old Dell Pentium4 with installed Windows and SATA)?

I wasn't able to read out ROM on first time. I tried several times and suddenly I got it. But I don't know what step I did before (maybe new reboot of PC with insulated HSA and deactivated HDD in BIOS). But I tried all possibilities (reboot PC many times with old and new PCB, with and without insulated HSA, with old and new drive connected to old and new PCB, only PCB without drive etc.)
Next step, i would have changed different assembly. Maybe PCB has got different component values, too. I can't verify them because of little package and no label.
Schematics would be fine.

I gave it back to my brother, but I could get it back tomorrow.
Data recovery is much too expensive. He told some laboratories and they said something about 900 €.
It's still in warranty. Maybe WD would change the drive and data will be lost. I have to talk to my brother about that situation.
My problem is time. I have to prepare for some important exams.
I will read that article, talk to my brother and answer tomorrow about next steps.
I appreciate your help.

That's I'm thinking of
Nevertheless, he's sad about data from last 3 years. He did a backup on exernal HDD, but deleted it for a huge project for which he needed much disk space.
This mishap happend few hours before next backup
I learned a lot how HDD is working.

@Spildit:
Are you able to read out ROM soldered on PCB with SOIC8-Clip? I'm thinking of power-supply for circuit. Does MCU work during connection through external programmer?

No. You should go to wingoz device manager..and look for the HDD. Doesn't matter when you plug it in (I plug it in after windows start because else it will remain stucked at BIOS checks. More, I plug the SATA in it after it finishes those clicks in which is not ready and f.u windows). Also it is recommended to disable the device in dev manager to stop windows accessing it. If the windows can't see at least the ROM version...WDR won't see nothing. I'm talking from experience. I was doing some coding on the principle that WDR works. ATA commands directly to the MOBO's ide controller. But if the PCB firmware (intern or external U12) is f. up..MCU can't handle any ATA command or Vendor Specific Commands. So if the hdd can't even reply to ATA IDent command...even with the ROM name..it means that the rom it's invalid...bad..not supported by the MCU in other words..the MCU is stacked with some errors at some flash execution point.



Adaptives could be or not inside ROM firmware. MCU loads the firmware via a bootstrap...a code which can be dumped from within MCU with a JTAG device.


In the PC's bios..the sata controller must be set as ide for the ports where you connect the hdd. ATA commands work with the controller set to IDE. But if you already dumped the frmw ..the MOBO's bios is correct.

Now I plan to write a function which checks the ROM.bin...but since te PCB identifies as WDC ROM..I assume that the file it's checked (by the kernel loader- the first code pointed by the first 32 bytes header in rom.bin file) for that stupid additive CRC

I'm to lazy at this hour to get the screw and unmount the pcb which by the way..lies on the floor with the cables hanging over the PC's opened case.

Tried a little time ago the ida on a random ROM..."kernel loader". the one about _dex_ states that it unpacks the other module. I'm a little overrun by the image I saw It requires deep knowledge of micro-controllers architecture and low level arm understanding. What ar I/O, IRQ etc, and how it looks the arm code when working with those entities. I'm just staring like a cow at it. Although the code is really small, couldn't find any unpacking routine ore where the code checks for the other code segments in the header.

Of course, power doesn't have to be connected to pcb. But ROM needs VCC to run. If MCU needs same voltage, let's say 3,3V, it would probably on the same power path and run, too. So it would interrupt communication between external programmer and ROM.

@louis:
Maybe WDR works with old PCB because I connected SATA to PCB after it ended up clicking. I will try again.