Artem Makarov aka Robin
During a short period of time several slim Seagate TLITE and NHAWK were brought for repair and data recovery. All of them had identical malfunction, at power on engine was accelerated, heads were unparked, discs recalibrated, but did not give the descriptor and as consequence, were not defined in BIOS.
Diagnostics showed that discs had infringements in the data service area, interfering with microprogram correct loading. Features of Seagate and new Maxtor (which actually is the same as Seagate) disc microprogram are as follows: in case of infringement in critical module service microprogram parts the store disconnects recording not to damage the user data. At the start moment some SMART tables should be rewritten, the disc cannot do it itself and does not run in operating mode to the user interface.
The data access can be received in several ways, for example it is possible to dissemble and modify executed code in a way to exclude complex initialization and show HDD readiness passing over errors. Error correction in service area helps the disc to be initialized correctly at the start.
Practice shows, that after the user information recovery discs not so willingly pass a factory self-testing cycle. Some of them even fail in the process. According to all above-stated I recommend concerning budgetary slim HDD with vigilance.
In the photo you can see Maxtor STM380815AS from the military unit from which data had been successfully recovered. Another one was unserviceable. I made pictures under different angle to show difference between a slim and a full-size disk (for those unaware). A slim HDD is approximately twice thinner than usual.