For my company, we manufacture SSD for different industrial sectors as a solution. Based on customer application, it could be a hardware or a firmware modification. if it required hardware, we change the initial design, CAD schematics for PCB, connector, Pin configuration if it different from write protect to standard secure erase, flash and, microcontrollers. However, if it is a Firmware modification to meet customer requirements. a revised FM had to assign a special number. the will prepare testing and verification of changes and submitted for approval to PM. Once it is approved SOP and BOM list will be updated with the new information. Also, PM will create a PCN includes all the changes and all the products will get affected by the change.