UNSOLVED
7920 boot issue ( flexbay nvme)
I have an issue with a 7920 which was working until I messed about with it 😕 may own bad .
Now I'm stumped and looking for an assist.. I fitted the rear four HDD setup and fitted non original to the spec nvme carriers flex bays on the front.
Have eventually got the thing working.
Except ..
Crucially
It won't boot from power up ...
It will boot IF
You choose to select the device as you would say you were choosing to boot from dvd / usb etc
Otherwise it goes into diagnostics
Very frustrating.
Any help would be appreciated.
I have taken every non essential thing out of the pc except it's graphics card ( which I've actually borrowed for another meantime) .
Ps has anyone ever worked out how to get the rebar thing working on a 7920
Many thanks
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Posted June 27th, 2026 09:20
For rebar, read this thread
Precision T7920 Workstation Resizable Bar Support | DELL Technologies
henry_collins
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Posted June 26th, 2026 22:47
This sounds like a broken UEFI boot entry rather than a hardware issue.
When you added the NVMe flex bays, the system likely stopped seeing “Windows Boot Manager” correctly, so it drops into diagnostics unless you manually pick the drive.
Check BIOS: Set boot mode to UEFI only, Put Windows Boot Manager first (not the NVMe device itself), If it’s missing, rebuild the boot entry using a Windows USB repair (bcdboot usually fixes it)
ReBAR on the 7920 is possible, but only with modded BIOS + compatible GPU, and results vary.