Firmware– It is a computer program, which is already embedded in a hardware device. Micro-controller is an example of it. It can also be presented on flash ROMs or as a binary image file that can later be uploaded by a user onto existing hardware.

Firmware failure is one of the most common hard drive failure and in many data recovery cases, we need to fix the firmware failure by rewriting donor good modules, regenerating original firmware modules or editing the modules.

Hard disk drives have a microprocessor, with internal “software” that runs them and make the drive work. The firmware instructions are embedded into read-only memory, this code is similar with the system BIOS.

The firmware is not fully resident in PCB, some parts are in sectors forming the so called Service Area (SA).

The firmware stored in SA is modular and we can find 3 kind of modules:

Data Modules – managing data area (eg. P-list and G-List)
Management Modules – managing the hdd basic functionality
Techno Modules – managing SA access operations

When some of the key firmware modules are damaged without backup and if those modules cannot be regenerated and then it’s not possible to recover the data.