HGST/WDC Ultrastar SN200 Recovery Guide – Persistent Internal Error / Diagnostic State / Missing Namespace
I wanted to document this entire recovery process because these drives can look completely dead while still being recoverable.
Recovered Drive:
- HGST/WDC Ultrastar SN200 7.68TB
- Model: HUSMR7676BDP3Y1
- Original firmware: KNGND110
Original Symptoms:
- Linux repeatedly logged:
"resetting controller due to persistent internal error"
- Controller appeared/disappeared every ~4.7 seconds
- No namespaces existed
- No nvmeXn1 devices
- BIOS could not see the drive
- Windows initially did not expose storage
- nvme-cli firmware activation failed
- Drive appeared stuck in recovery/diagnostic/SBL mode
Initial Linux Environment:
- Dell PowerEdge R740XD
- Ubuntu Linux
- nvme-cli installed
- HGST HDM installed
Linux consistently showed:
- PCIe enumeration worked
- Controller object existed
- NVMe admin queues initialized repeatedly
- Firmware subsystem partially alive
Intermittent successful commands:
- nvme id-ctrl
- nvme fw-log
- fw-download transport
Valid identify data repeatedly returned:
- SN: SDM0000882DA
- Model: HUSMR7676BDP3Y1
- FW: KNGND110
Important discovery:
The controller itself was NOT dead.
Firmware Package Findings:
KNGND122.bin was NOT a raw firmware image.
It was a packaged enterprise firmware bundle containing:
- FWHEADER.bin
- PROC0-15.bin
- SECURITY.bin
- FCC.bin
- StringTable.csv.gz
Extracted strings strongly suggested diagnostic/recovery behavior:
- "SYS: Go into SBL mode"
- "SYS: Crash Occurred"
- "Overlay Init Done"
- "Error: Invalid Overlay"
This strongly suggested:
- recovery firmware state
- corrupted operational runtime state
- failed namespace/FTL initialization
- NOT dead hardware
Linux Attempts That DID NOT Fix It:
- nvme fw-download
- nvme fw-activate
- namespace creation commands
- APST disable
- ASPM disable
- PCIe secondary bus reset
- HDM on Linux
Interesting Linux Findings:
- fw-download transport actually succeeded once
- firmware activation failed with invalid image
- Linux HDM could never enumerate the device
- PCIe bridge reset triggered GHES fatal hardware errors
- Controller repeatedly initialized:
"56/0/0 default/read/poll queues"
Critical Hardware Change:
The major breakthrough came after:
- moving the drive OUT of the Dell server
- moving it OUT of Linux
- placing it into a Windows workstation
- using a direct PCIe 3.0 U.2 adapter card
Hardware used:
- AMD 7950X workstation
- direct PCIe 3.0 U.2 adapter card
- no enterprise backplane/riser complexity
This appeared to provide:
- cleaner PCIe initialization
- direct controller access
- better compatibility with HGST tooling
- less PLX/backplane interference
Critical Windows Discovery:
Windows Device Manager successfully detected:
"WD Ultrastar SN2xx PCIe SSD Controller"
This was HUGE because Linux HDM never successfully enumerated the drive.
Required Software:
- HGST Device Manager (HDM) 3.4
- Administrator CMD/PowerShell
Successful HDM Scan:
Command:
hdm scan
HDM successfully detected:
- NVMe controller
- firmware slots
- stable controller UID
- stable device path
Initial Firmware Slot State:
Running Firmware Version = KNGND110 (Loaded from Slot 5)
Firmware slots:
- Slot 1 (Read-only)
- Slot 2
- Slot 3
- Slot 4
- Slot 5
All showed KNGND110.
Critical Discovery:
Slot 5 appears to behave like:
- recovery slot
- fallback slot
- degraded runtime state
The drive was trapped booting from Slot 5.
THE RECOVERY PROCESS:
This was the key fix.
Step 1:
Activate Slot 2:
hdm manage-firmware --activate --slot 2 -a @nvme0
IMPORTANT:
Do a FULL shutdown after each slot change.
NOT reboot.
Command:
shutdown /s /t 0
Wait ~30 seconds before powering back on.
Result:
- controller behavior improved slightly
- BIOS still inconsistent
Step 2:
Activate Slot 3:
hdm manage-firmware --activate --slot 3 -a @nvme0
Again:
FULL shutdown afterward.
Major behavior changes occurred:
- BIOS started detecting the drive
- Windows became much more stable
- controller reconnect storms mostly stopped
- namespaces began partially initializing
Final Stable State:
Eventually Slot 4 became the healthiest operational slot.
Final stable behavior:
- BIOS fully sees drive
- namespaces restored
- full 7.68TB visible
- stable controller enumeration
- stable PCIe link
- Windows Disk Management detects drive normally
Final HDM State:
- Running Firmware Version = KNGND110 (Loaded from Slot 4)
- Namespace Count = 1
- Capacity = 7681501126656
Important Lessons Learned:
- These drives can look COMPLETELY dead while still recoverable.
- Missing namespaces does NOT mean dead NAND.
- BIOS invisibility does NOT mean dead controller.
- Linux recovery tools were insufficient in this case.
- Windows HDM was the major breakthrough.
- Firmware slot switching was the real fix.
- Slot 5 appears to be a recovery/fallback runtime state on these drives.
- Direct PCIe access mattered enormously.
Firmware Update Notes:
KNGND122.bin could NOT be directly loaded using the current HDM workflow.
Commands like:
hdm manage-firmware --load --file "C:\KNGND122.bin"
currently failed with:
"Required command parameter is missing --load"
Still investigating:
- exact firmware package workflow
- whether newer tooling is required
- whether diagnostic-clear workflow is mandatory before loading
Current recommendation:
If your SN200:
- loops resetting
- has no namespace
- BIOS cannot see it
- Linux repeatedly resets controller
DO NOT immediately assume it is dead.
Try:
- Windows
- HGST HDM
- Direct PCIe U.2 adapter
- Firmware slot switching
- Full shutdowns between slot changes
That combination was ultimately the recovery breakthrough.
