Phison Ps2251-19 May 2026

In system device managers, it appears as:

The Phison PS2251-19 (marketing name) / PS2319 (silicon marking) is a highly integrated, cost-optimized USB 3.2 Gen 1 controller designed for mainstream USB flash drives. It bridges the gap between basic USB 2.0 controllers and high-end, SSD-level USB drives, offering a compelling balance of performance, power efficiency, and advanced features.

Q: MPALL says "Device not match" or "Not supported".
→ You need a newer MP version (3.16+). Older ones don’t recognize PS2319. phison ps2251-19

Q: Drive works but write speed dropped to <10 MB/s.
→ Run STTool → Clear Bad Column → Erase All (full wipe), then re-format with MPALL.

Q: USB-CD boots, but OS can’t see second partition.
→ Windows only sees the first partition of a removable drive. Use Mode 7 (Fixed Disk) before creating CD-ROM. In system device managers, it appears as: The

Q: Linux / macOS support?
MPALL tools are Windows-only. Use lsusb to confirm Phison 0x2319. You can use sg3_utils to issue low-level SCSI commands, but mode switching is unreliable. Best to perform setup on Windows once.

| Controller | Interface | Max Read | Channels | DRAM | Typical Use | |------------|-----------|----------|----------|------|--------------| | PS2251-19 | USB 3.2 Gen 1 | 400 MB/s | 2 | No | Mainstream flash drives | | PS2251-07 | USB 3.0 | 200 MB/s | 2 | No | Older high-speed drives | | PS2251-09 | USB 3.1 Gen 1 | 300 MB/s | 2 | No | TLC-optimized | | PS2251-11 | USB 3.1 Gen 1 | 380 MB/s | 2 | No | Better random read | | PS5012-E12 | PCIe 3.0 x4 (SSD) | 3400 MB/s | 8 | Yes | Not for USB flash | → You need a newer MP version (3

The Phison PS2251-19 is a single-chip USB Flash Drive (UFD) controller. It serves as the bridge between the NAND Flash memory (where your data is stored) and the USB interface (how your computer talks to the drive).

It was designed specifically to address the market need for affordable drives that offer USB 3.2 Gen 1 (formerly known as USB 3.0) speeds, replacing the slower USB 2.0 legacy controllers without driving costs up to the level of high-end Solid State Flash (SSF) controllers.

In the world of removable storage, the "brand" on the outside of the USB drive often tells you very little about what is inside. The true performance, reliability, and feature set are dictated by the controller chip. One of the most ubiquitous and influential controllers in the transition to high-speed USB 3.2 Gen 1 storage is the Phison PS2251-19 (often shortened to PS2319).

Developed by Phison Electronics Corp, the Taiwanese giant known for dominating the NAND flash controller market, the PS2251-19 has become a staple for mid-range USB flash drives. But what makes this chip tick, and why is it found in millions of devices worldwide?