Here is the situation.

unRaid has been working on this hardware extremely well for some time, however, a couple of weeks ago i added some drives to a controller that was in the system and unused.

 

Those drives were throwing up a lot of errors, so as I was going on vacation.  I simply disconnected them. (There were in caddies on a PowerEdge server, so I removed the caddies and put blank ones in place.

 

While on vacation, I looked at the errors and it indicated that the cables were probably at fault, and as I had never used this controller and cables,  I ordered up some new cables for my return from vacation.

 

Fast forward to today, I retuned home. I shut down unraid, and swapped the cables over. - I had also has a new riser card arrive, so i swapped the controller into a different slot.

 

I tried to boot up and it hung at some point - I didn't notice at what point.

 

I decided I'll mess with this another time, so removed the unused controller, and reverted everything else back to how it was.

 

unraid will still not boot.

 

It is starting to boot, but then after it goes to Loading /bzroot..ok" it goes no further.

 

I downloaded a backup of the flashdrive from unraid connect, put all of the old files into a folder called "OLD" and put all of the files from the backup onto the root part of the flash drive.

 

However I am still getting the same problem, It goes as far as the "loading/bzroot...ok"

 

I did a quick search on hear and it mentioned renaming the efi- to efi, i tried that but no change. - The Bios is set to boot in uefi mode. - I don't believe any bios settings have changed

 

Any ideas on how to progress?

 

I cannot add diagnostics... but if there are any files that would help please let me know.

 

 

 

 

make sure and check another usb 2.0 slot.

Unraid doesn't support sas muti-pathing.

Uraid default usb boot setup is non uefi. Try disabling secure boot and enabling csm compatibility.
-Once in unraid web UI > Main > Flash you can permit uefi and use uefi at bios boot options.

 

If you get the 
bzroot...ok

but nothing else then the system may have lost read access to the usb and was unable to continue due to missing USB drive.

So first try another usb 2.0 slot (there have been noted issues of 3.0 slots....

 

Hi, Thank you for your reply.

 

Still puzzled here.

 

I have tried the unraid boot flash in all 5 of the USB slots and get the exact same result, i.e. stopping after the Loading /BZroot... OK - There are 2 o nthe front that i think are USB 2 and the others are all usb 3, but I get the same result on all slots.

 

I switched to booting in legacy bios, and it would not get past the drive controllers and would not get as far as booting unraid.

 

So I tried to get drastic and removed both SAS/SATA controllers and again, it made no difference (it was working with both of these previously)

 

I put the unraid boot flash onto another pc, and it booted past the problem point, but not a complete boot, it hung not long after saying no pools available. (there was no SAS controller or drives in this PC, so not sure if that was the problem.

 

So there must be a setting in the server PC Bios that has changed somehow, causing it to stop after the Loading /BZRROOT section.

 

Here are some screenshots of bios settings, the Drive controllers are not installed when  I took the screenshots, but I don't think that matters?

 

 

per your pictures. 
Some are guesses others are questionalbe...

I would use boot mode bios. 

-Unless your sure unraid has the correct syslinux for efi boot.

https://docs.unraid.net/unraid-os/troubleshooting/boot-issues/

 

If keeping uefi, click uefi setting and make sure secure boot is off, fast boot is off and uefi csm (compatibility is enabled)

-Looks like secure boot is disabled. but should be in custom no standard. Shouldn't be a problem. I have seen weird Linux stuff due to it secure boot is more a windows things.

 

see also :

https://docs.unraid.net/legacy/FAQ/usb-flash-drive-preparation/

you may not have the usb prepped right (can it boot on another system?)

 

I would disable security freeze lock

-The "Security Freeze Lock" option in Dell PowerEdge BIOS, found within the SATA Settings, is a security feature that sends a command to embedded SATA drives during the POST (Power-On Self Test) to prevent unauthorized access or modification of drive data. This feature is typically enabled by default and is only applicable when the AHCI Mode is selected for embedded SATA drives. 

 

I would enable write cache

-The "Write Cache" BIOS option on Dell PowerEdge servers, when applicable, determines how the controller handles write operations to the storage device. It's a setting within the BIOS that affects how data is cached and written to the disks, impacting performance and data integrity. 

 

I would turn on TPM security as well

-The TPM Module can assist in cryptography latter.

 

I would set AC power recovery to on or off not last due to memory...

-Set to on to power on after power loss

 

I would disable x2apic mode.

-x2APIC can improve efficiency in systems with multiple processors and high core counts... https://serverfault.com/questions/873664/when-to-use-x2apic-mode

Its a personal preference for me for iommu and io2apci handshakes to pass pcie devices.

 

at the grub screen you can edit the unraid boot line you can try adational grub syslinux commands

 

use "Tab" key and edit the OS boot options.



Examples to try:

acpi=force acpi_osi=Linux usbcore.autosuspend=-1

so after /bzroot ...linux grub sysliux commands...

to disable the usb from entering a power sleep mode and to for linux to use the OSI linux ....

you can even try noapic option at the grub boot menu.

Later once unraid has booted on your platform you can set the grub options at every boot...

 

 

as either you have hardware issues, a bios misconfigurations, or your usb is bad try to boot your unraid on anther system to rule out a bad thumb drive.

OK, got it nailed down.... Faulty stick of RAM.

 

Very strange though as the BIOS RAM check was passing all of the RAM.

 

Thank you for your help.