Years ago, SATA drives using the Phison S11 controller had a notorious bug. If the drive lost power while executing a specific trim command, the . The drive would show up as “0MB” or “SATA SSD” in BIOS with no capacity. Data recovery was nearly impossible without reflashing the firmware (which wiped the data).
Phison designs controllers that are highly versatile. A single Phison controller, such as the E18, might be used by a dozen different drive manufacturers (Adata, Corsair, Seagate, etc.). Each manufacturer might use different brands of NAND flash memory (Micron, Kioxia, Samsung) on their drives. The firmware acts as the translator, allowing the controller to communicate effectively with whatever specific NAND configuration is soldered onto the PCB. phison firmware
Phison firmware is the "brain" of the SSD, managing critical background tasks that ensure data integrity and speed: Flash Translation Layer (FTL): Years ago, SATA drives using the Phison S11