Hard Drive Firmware Data Recovery Case Study: Seagate ST3750528AS

Hard Drive Firmware is the operating system of the hard drive. It is the first thing on the drive’s platters the magnetic read/write heads try to read when the drive is powered on and spins up. If the read/write heads cannot shake hands with the firmware, whether due to a failure of the heads themselves or due to corruption or damage to the firmware sectors, the drive is brain dead: The lights are on, but nobody’s home.

---

---

When you connect a brand new, fresh-off-the-assembly-line hard drive to your PC and Windows prompts you to initialize or format the device before you can use it, it is because the drive is blank. But when you connect a hard drive you’ve been using for years to your PC and Windows spits out an error message prompting you to initialize the device before you can use it, it is because something has gone wrong.

Whenever you connect a hard drive to your computer, your computer will look for the drive’s partition table and the boot sectors for each partition. Basically, it is looking for the hard drive’s floor plan so it can easily navigate the drive’s architecture.

Computers are very incurious creatures, though. If your computer can’t find the information it needs where it expects to find it, it just throws up its hands and gives up, assumes it’s looking at a vacant lot instead of a house, and then says, “Well, I can’t figure out how your hard drive is formatted, so I guess this drive is blank. Do you want me to format it?” Of course, this is a dangerous question to ask when you know that your drive does, in fact, have data on it.

When a hard drive suddenly shows up as blank, there can be a myriad of potential culprits such as read/write head failure, platter damage, or corruption of the drive’s partition table or boot sector.  In this case however, an evaluation of the client’s failed hard drive by our data recovery engineers showed that the reason the drive would not initialize was due to a misbehaving part of the hard drive firmware.

Infirm Hard Drive Firmware

One of the many tasks of firmware is to tell the hard drive what to do when it encounters a sector that can no longer have data written to it or read from it. The firmware keeps a list of which sectors have gone bad and need to be reallocated to a different spot on the disk.When the hard drive encounters a bad sector, it tells the firmware about it and promptly goes about its merry way. But sometimes this process goes awry.

In this client’s case, the hard drive’s read/write heads encountered a new bad sector and asked the firmware what to do. The firmware pulled up the list of bad sectors it kept so it could add the new sectors to it, but the list had become corrupted. The firmware wasn’t programmed to deal with this situation, so it panicked. In this case, the client’s hard drive showed up as “blank” because it had suffered what is more or less the hard drive equivalent of the dreaded “Blue Screen of Death” —and would keep crashing every time the drive’s read-write heads encountered any bad sector.

Repairing failed hard drive firmware may not require any mechanical work on the hard drive, but it is a delicate and difficult procedure nevertheless. Just as in replacing a hard drive’s set of failed read/write heads or repairing its electronics, one wrong move by someone who isn’t quite sure what they’re doing can turn a hard drive into a paperweight. Furthermore, while the firmware on a hard drive does the same job as the operating system on your PC, there is no firmware equivalent for the Windows repair disk or recovery partition you would use to get your PC working again after an O/S failure. Luckily, we have computer scientists who have spent years dealing with firmware issues and have grown very skilled at repairing them.

Our data recovery engineers repaired the hard drive firmware bug affecting the client’s Seagate hard drive and coaxed the drive into functioning properly again. Firmware failure can come hand in hand with read/write heads failure and platter damage, but in this case, the rest of the drive seemed perfectly healthy.

There were only a few hundred bad sectors on the drive’s platters for our data recovery engineers to deal with. These sectors had likely gone bad as a result of natural wear and tear on the drive’s platters and not of any specific mechanical failure. We were able to recover 99.6% of the client’s files after reading 11.2% of the binary sectors on the drive, and so we ended up rating this hard drive firmware data recovery case a high nine on our ten-point scale.