The SM3257EN is a feature-enhanced USB2.0 Flash Disk controller with high compatibility and best
performance designed to support MLC and TLC NAND flash. The controller also supports high speed
ONFI 2.x and Toggle mode NAND. Compliant with USB version2.0 specification and USB Mass Storage Class version 1.0 specification, the SM3257EN provides write protect, PC boot-up from USB2.0 Flash
Disk, password protection, secured partitioning functions, etc.

Reference Site : //flash-extractor.com/forum/viewtopic.php?t=5616