Windows 11 Reg fix for SN770, SN580 (and other) HMB force to 64M

WD-HMB64M.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorPort]
"HMBAllocationPolicy"=dword:00000002

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\stornvme\Parameters\Device]
"HostMemoryBufferBytes"=hex(7):56,00,45,00,4e,00,5f,00,31,00,35,00,42,00,37,00,\
  26,00,44,00,45,00,56,00,5f,00,35,00,30,00,31,00,37,00,26,00,52,00,45,00,56,\
  00,5f,00,3f,00,3f,00,20,00,36,00,37,00,31,00,30,00,38,00,38,00,36,00,34,00,\
  00,00,56,00,45,00,4e,00,5f,00,31,00,35,00,42,00,37,00,26,00,44,00,45,00,56,\
  00,5f,00,35,00,30,00,34,00,31,00,26,00,52,00,45,00,56,00,5f,00,3f,00,3f,00,\
  20,00,36,00,37,00,31,00,30,00,38,00,38,00,36,00,34,00,00,00,00,00

I run Server 2025, it's affectet too, as it's also 24/H2

Western Digital has released a firmware update that limits HMB to 64MB and potentially other fixes, that should be used and not this anymore.

Western Digital has released a firmware update that limits HMB to 64MB and potentially other fixes, that should be used and not this anymore.

Can you tell me if I need to delete the registry entry before putting this update?

I applied the firmware update, then removed the reg changes with https://gist.github.com/nissel/a20a6ca5f8aeb8802554f239a28833bd then rebooted

But they aren't going to interact in any strange way, the firmware patch appears to just limit the buffer to 64MB so fixes the issue in exactly the same way.

I wouldn't want to install a firmware update in a system that's crashing randomly, as if it did crash during the update that would probably be very bad. So id say it's best to leave the reg changes there until you update the firmware.

I applied the firmware update, then removed the reg changes with https://gist.github.com/nissel/a20a6ca5f8aeb8802554f239a28833bd then rebooted

But they aren't going to interact in any strange way, the firmware patch appears to just limit the buffer to 64MB so fixes the issue in exactly the same way.

I wouldn't want to install a firmware update in a system that's crashing randomly, as if it did crash during the update that would probably be very bad. So id say it's best to leave the reg changes there until you update the firmware.

Well I wouldn't install an update on a system that could shut down at any moment either :). If you modify the registry, the changes are applied only after a reboot. But I'll do as you said anyway. Thanks!

Anyone know what these values should be for an sn550 drive? I've also been affected by BSOD but no firmware update. New HWinfo update reports 200mb hmb even if it set all variables.

Anyone know what these values should be for an sn550 drive? I've also been affected by BSOD but no firmware update. New HWinfo update reports 200mb hmb even if it set all variables.

Just try to disable HMB, setting the limit didn't help me initially either, although I have an SN770

Anyone know what these values should be for an sn550 drive? I've also been affected by BSOD but no firmware update. New HWinfo update reports 200mb hmb even if it set all variables.

check the device manager

Thanks, value that worked for the sn550 if anyone else is interested is:
VEN_15B7&DEV_5009&REV_?? 67108864

SN530 too seems to be affected, the value to add to HostMemoryBufferBytes is VEN_15B7&DEV_5008&REV_?? 67108864

Possibly you will need to check your PCI device id in device manager.

You might to experiencing a different issue, as WD don't list your drive as affected ? Have you checked your current HMB allocation?

Have you checked your current HMB allocation?

This is what I see in HWinfo with the fix:

Without the fix I get IO1 Initialization failed BSOD

Interesting looks like WD have missed some affected models. You could try and let them know via a support ticket.

But I'm not 100% sure it's a problem, for example now successfully booted with HMB 200MB (which still seems abnormal to me) without BSOD: