The SM2259XT is a DRAM-less SATA SSD controller from SMI (Silicon Motion). "Firmware fixed" typically refers to repairing a corrupted translator (MPT) or bricked state due to power loss or bad blocks.
The write-up verifies the implementation of a revised mechanism. sm2259xt firmware fixed
: The drive shows up as "SMI ROM" or "SM2259XT" rather than its actual brand name. Size Mismatch The SM2259XT is a DRAM-less SATA SSD controller