Phison | Ps2251-07 Firmware Update Tool ((link))

Flashing firmware is risky and should be a last resort. Using the wrong version can permanently brick the device.

However, the most vital application of the tool for the average consumer is "unbricking." It is not uncommon for a USB drive to be accidentally unplugged during a write operation or to suffer a power surge, resulting in corrupted firmware. When this happens, the drive may appear as an "Unknown Device," report a capacity of 0 bytes, or fail to mount entirely. Standard formatting tools provided by the operating system cannot fix this because the device's internal logic is scrambled. Here, the Phison tool serves as a defibrillator. By forcing the controller into a specific mode, the tool can re-flash the firmware, effectively resetting the device to its factory state. Phison Ps2251-07 Firmware Update Tool