This is one real case study on how to recover lost data from Western Digital USB3.0 hard drives whose PCB number belongs to 1961 series.

HDD ID: 2.5” USB3.0 Hard Drive
Family-Null; Model: WDC WD20NMVW-11AV3S2; Capacity: 2TB
PCB: 1961

The engineer changed the 1961 USB PCB to 1933 SATA PCB and moved the ROM chip-U12 to the SATA PCB as well. Read more