Firmware failure on Western Digital drive

We have been working to rebuild the firmware on a failed Western Digital HDD, but to no avail.  The firmware resides in the motor chip that has blown and this can be one of the most testing data recovery procedures - contrary to popular belief!. 

You might be surprised to find out of how a hard drive - as a separate device - resembles the actual computer. Whether the drive is connected to a computer through an external box, or just powered from a separate power supply, the first thing it does is to start booting its own internal program, a firmware that acts just like a computer OS. What happens if the internal process of drive initialization by its firmware failed by some reason? Then the CMOS will not be able to identify the failed hard drive. The computer will skip on such drive, and may give you an error message.

The problem with these Western Digital drives is that the firmware is built into the motor chip. As the firmware is corrupt, the drive is failing even though its electronic and mechanical components are fully functional. This firmware failure appears to have been caused by self-corruption due to excessive and prolonged use. Whilst we can find firmware updates for this drive from Western Digital - updates do not fix firmware failures. We had to find a working copy of the firmware and replace the motor chip. Thankfully we had a replacement in our spares library in which we have over fourteen thousand spares cataloged!