SSD Controller Technical Reference
Phison PS5021-E21T Controller Reference
The Phison PS5021-E21T is a budget PCIe Gen4 DRAM-less controller relying on Host Memory Buffer (HMB) to store translation tables in the host PC's system RAM. It gained infamy from a confirmed PCIe 4.0 data loss bug affecting 1TB M.2 2230 models (discovered by PCPartPicker, acknowledged by Phison). The bug triggers at Gen4 speeds but not Gen3, making Steam Deck (Gen3) less affected than ROG Ally (Gen4). ACELab's PC-3000 SSD supported-controller list does not currently cover this controller. For context on the SSDs we do recover, see our SSD data recovery page.
Phison PS5021-E21T is not on the current PC-3000 SSD supported-controller list
Phison PS5021-E21T does not appear on the current ACELab PC-3000 SSD supported-controller list (PC-3000 SSD / PC-3000 SSD Extended 3.8.10) as of 2026-05-12. Case-by-case feasibility only. Contact us before shipping anything and we will tell you in writing whether we can do anything for your specific drive.
Source of truth: ACELab PC-3000 SSD supported-drives list. Internal evidence file: src/lib/ssd-support-matrix.ts.
Phison PS5021-E21T Specifications
| Manufacturer | Phison |
| Interface | NVMe Gen4 |
| NAND Types | 3D TLC, 3D QLC |
| DRAM Cache | No (DRAM-less) |
| Channels | 4 |
| PC-3000 Support | Limited / Generic NVMe |
| Chip-Off Viability | Not viable (AES-256 hardware encryption) |
PC-3000 support under development. DRAM-less HMB design. Critical for M.2 2230 drives in Steam Deck, ROG Ally, and Surface Pro.
Affected SSD Models
The Phison PS5021-E21T is deployed in the following consumer drives. A failure in this controller impacts access to the NAND flash on these specific models.
| # | Drive Model | Interface |
|---|---|---|
| 1 | Sabrent Rocket 2230 | NVMe Gen4 |
| 2 | Corsair MP600 Mini/Core | NVMe Gen4 |
| 3 | Crucial P3/P3 Plus | NVMe Gen4 |
| 4 | Kingston NV2 (some variants; also ships with SM2267XT, E19T, SM2269XT) | NVMe Gen4 |
| 5 | Team Group MP44S | NVMe Gen4 |
Common Failure Modes and Symptoms
Each failure mode below describes a specific way the Phison PS5021-E21T fails and the symptoms you will observe. If your SSD matches any of these patterns, do not run recovery software; it cannot communicate with a dead controller. See the zero-byte SSD diagnostic reference for a deeper technical explanation of controller and FTL failures.
- PCIe 4.0 permanent data loss bug
Reproducible permanent data loss bug discovered by PCPartPicker. Under specific heavy sequential write/read workloads at PCIe 4.0 speeds, the controller fundamentally corrupts its FTL state and generates physical bad block flags. The bug does not reproduce at PCIe 3.0 speeds (which is why Steam Deck users rarely encounter it, while ROG Ally users do). Data lost to this specific bug is completely unrecoverable.
- Data silently corrupted during heavy workloads
- Files unreadable after writing
- Drive appears healthy but data is gone
- Bad Block Errors in Windows Event Viewer
- Firmware failure / 0MB detection
Service Area corruption beyond the controller's self-repair capability causes the drive to enter ROM Mode. The drive reports 0MB capacity or fails to enumerate in BIOS entirely. Common in aftermarket 2230 SSD upgrades for Steam Deck, ROG Ally, and Surface Pro.
- SSD shows 0MB capacity
- RAW partition after power loss
- BSOD on boot
- Steam Deck not booting after SSD upgrade
- HMB sync failure from system crash
The DRAM-less E21T stores FTL mapping tables in the host computer's system RAM via Host Memory Buffer. A hard crash, unexpected reboot, or sudden power loss deallocates this RAM before the controller can flush the mapping state to NAND, resulting in catastrophic FTL corruption. The dispersed metadata (designed for HMB, not local cache) makes reconstruction slower.
- Drive not detected after hard crash or freeze
- Drive dead after unexpected reboot
- 0MB capacity in BIOS after system crash
- Files missing after blue screen event
How Is Data Recovered from a Failed Phison PS5021-E21T SSD?
Data is recovered from a failed controller SSD by keeping the original board alive, reading controller state with PC-3000 SSD, and rebuilding the Flash Translation Layer from surviving NAND metadata. If firmware access requires Safe Mode or a volatile loader, that work happens before imaging. When the controller also handles decryption, chip-off returns unreadable data.
At our Austin, TX lab, the goal is to keep the original controller stable long enough to expose ROM state, firmware behavior, and NAND metadata without letting the drive keep writing to itself. Our SSD data recovery overview covers lab intake and triage, why SSDs report 0 bytes explains capacity failures, and how SSD controller encryption works explains why the original silicon matters.
- Phison PS5021-E21T failures usually break the Flash Translation Layer, firmware boot path, or local power rail before macOS or Windows sees a mountable volume. Symptoms such as Data silently corrupted during heavy workloads, Files unreadable after writing, Drive appears healthy but data is gone are useful to recognize, but on this controller they do not unlock a tooling path we can offer in-lab.
- Phison PS5021-E21T is not on ACELab's PC-3000 SSD supported-controller list (PC-3000 SSD / PC-3000 SSD Extended 3.8.10). Without firmware utility coverage, the controller's mapping tables, internal loader, and any factory diagnostic mode are inaccessible to us, which means no firmware-level recovery is on the table.
- Phison PS5021-E21T fuses AES-256 keys to the controller silicon, so desoldering the NAND chips returns ciphertext that cannot be decrypted without reviving the original controller through tooling we do not currently have for this controller.
Frequently Asked Questions
Can software recover data from a dead Phison PS5021-E21T?
Why not use chip-off recovery on Phison SSDs?
Does Rossmann recover data from Phison PS5021-E21T drives?
Can you recover deleted files from a Phison PS5021-E21T SSD?
Other Phison Controllers
Phison PS3111-S11
SATA · Kingston A400, PNY CS900 (some variants)
Phison PS3110-S10
SATA · PNY CS1311/CS2211, Patriot Ignite
Phison PS5012-E12
NVMe Gen3 · Corsair Force MP510, Sabrent Rocket NVMe
Phison PS5016-E16
NVMe Gen4 · Corsair Force MP600, Sabrent Rocket 4.0
Phison PS5018-E18
NVMe Gen4 · Corsair MP600 Pro/XT, Sabrent Rocket 4 Plus
Phison PS5027-E27T
NVMe Gen4 · Micron P310 2280, Timetec Gaming SSD (Gen4)
Have a Phison PS5021-E21T drive?
We do not currently offer in-lab recovery for Phison PS5021-E21T SSDs because the controller is not on ACELab's PC-3000 SSD supported-controller list. Contact us before shipping anything; we will confirm in writing what we can and cannot do for your specific drive.