For many of  our professional data recovery engineers, we may met such data recovery cases on WD drives whose original ROM is missing due to damaged PCB. If the original ROM is missing, What will you do?  Many people tried to install another PCB of the same family but failed to solve the problem, so what are the solutions?

Actually if the drive needs to start normally, the heads map, the adaptive settings of in ROM module ID=47h for all heads, the firmware version in the ROM and the overlays within the SA in its HDA need to be matching. Maybe the following can give us some idea of how to restore the original ROM content.

1st, Install one donor PCB

What’s a donor PCB here? The same drive family. The best is to make sure the PCB number is the same so you can make sure it’s matching. After the donor PCB installation, you may get different results:

01: The drive is detected incorrectly returning its factory alias or empty HDD ID.  However, the motor keep spinning and some professional firmware repair tools are able to read the module 01;

02: Similar like above but the tools are not able to read the DIR module; this can be caused by a mismatch of adaptive data or firmware incompatibility with the heads controller chip in the HDA. Recording another ROM may help in such cases;

03: Detected incorrectly and the motor is stopped. This can be caused by a mismatch between the heads map defined in ROM module 0Ah and the actual configuration. So you need sometimes to edit the heads map; It can be also caused by a damaged preamplifier chip of the head stack. You may identify the chip damage by two attempts to spin the motor. If the heads get stuck in the surface or the motor seizure occurs, the firmwares 5 attempts to start. Then you may consider a head replacement to fix the problem;

04: The best and rare situation is that you can access to the user data without obvious problems after the donor PCB installation. How cool is this one to be a donor because you have got the firmware version compatible, the adaptive settings very close to the original configuration, all heads are functional and corresponding to the original heads map.

2nd, Read the modules: ROM image module 0109h; 0102h(containing the actual factory-defined heads map);0103h(a copy of adaptive settings from module 047h); 0105h(SA translator copy from ROM module 030h) and 0107h(00Bh copy defining the map of ROM modules and the placement of SA copies);

3rd, Rebuild ROM

4th, Record assembled ROM and  its modules. Write the ROM first and then record the ROM modules while the HDD is still powered-on.

Anyway, it’s not easy to fix this data recovery case while the original ROM is missing,  you need not only professional data recovery tools, but above method is not universal and sometimes we fail as well. So if you have any good customized solutions for the ‘Original ROM is missing’ issue, please share here with us, thank you.

By the way, I must thank Data Recovery Salon a lot for providing this great platform and share with us so much useful data recovery ideas or useful tips which help a much higher success in our data recovery lab. I will continue sharing mine here as well.