I have been running unraid for a while now.  Never really bothered with how it was booting.

 

I have recently tried to create a VM with GPU pass through and had issues so found out that my server is booting in UEFI mode and i should change it to Legacy.

 

So I went into the BOIS of my PC and Legacy Mode is Turned on.  however in the boot options I dont see my USB as Legacy only UEFI.

 

I can however press F8 and use the boot override to boot in to Legacy.  does anyone know why this may be?

 

I unchecked the boot in UEFI in unrad and that doesn't help either except now I have to force the boot in Legacy but still no option to select legacy in the the boot Menu.

 

My Motherboard is: ASUS X99-M WS/SE

 

 

19 minutes ago, SohailS said:

So I went into the BOIS of my PC and Legacy Mode is Turned on. 

 

What do you actually mean by this?   To boot in legacy mode then CSM support must be enabled.  A BIOS option called Legacy USB support is not what is needed.

Just now, itimpi said:

 

What do you actually mean by this?   To boot in legacy mode then CSM support must be enabled.  A BIOS option called Legacy USB support is not what is needed.

 

Yes by enabling Legacy I mean I have enables CSM.  

 

it still wont let me boot from the USB via Legacy (it does only if i use the boot override) only shows me the UEFI option

2 minutes ago, SohailS said:

 

Yes by enabling Legacy I mean I have enables CSM.  

 

it still wont let me boot from the USB via Legacy (it does only if i use the boot override) only shows me the UEFI option

Have you made sure that the EFI folder on the flash has the trailing '~' character to disable the Unraid UEFI boot option?   If that does not work and you can do it via a Boot over-ride then it feels like a BIOS bug,.

1 minute ago, itimpi said:

Have you made sure that the EFI folder on the flash has the trailing '~' character to disable the Unraid UEFI boot option?   If that does not work and you can do it via a Boot over-ride then it feels like a BIOS bug,.

Yes it has the "-", it may be a BIOS thing yes as i can use the boot override to boot it in Legacy.  not sure what I can try next

when creating the USB will UNRAID create it both for Legacy and UEFI im wondering if I may have made it UEFI only??

1 minute ago, SohailS said:

when creating the USB will UNRAID create it both for Legacy and UEFI im wondering if I may have made it UEFI only??

I think the default is legacy mode which leaves the trailing '~' on the EFI folder (but you specify you want UEFI boot enabled at creation time.)   You then have to remove that for UEFI boot to work.

5 minutes ago, SohailS said:

im wondering if I may have made it UEFI only??

Legacy will still boot with UEFI enable.

6 minutes ago, JorgeB said:

Legacy will still boot with UEFI enable.

Is that always true?   I know it is on my systems, but I always assumed (maybe wrongly) that there was a good reason Limetech did not always leave both options enabled on the flash drive.

13 minutes ago, itimpi said:

Is that always true? 

Yes.

 

13 minutes ago, itimpi said:

there was a good reason Limetech did not always leave both options enabled on the flash drive.

Tom mentioned concerns over some buggy UEFI BIOS, which should be irrelevant by now.

if i have disabled UEFI in UNRAID and it adds the - to the EFI folder should my motherboard not even see it in the BIOS? as it still sees it as an option

It should still list the USB device (without UEFI in front), if CSM boot is enable.

4 hours ago, JorgeB said:

It should still list the USB device (without UEFI in front), if CSM boot is enable.

this maybe my issue.  even though I have the - before the EFI my BIOS still sees the UEFI boot partition and not the Legacy.  again i can still boot the legacy if I force boot to it from the F8 Boot Menu

Looks like a BIOS issue, bug or not correctly configured, looks for a BIOS update and re-check config.

Since this is a top search result I'll give an answer in here.

So I spend a lot of time trying to boot in Legacy mode.

 

Issue is very simple.

Some flash drives will not be seen as bootable in Legacy mode no matter what. 

Tried 4 different drives.

Only one of them booted in legacy mode, the other 3 only in UEFI. 
Experimented with those 3, deleted partitions, formatted them, reinstalled unraid from creator, run the `make_bootable` script, nothing helped. Just totally nothing.

The one that worked in Legacy was (no surprise) the oldest one I have. Probably 7-10 years old

3 hours ago, BeersTeddy said:

Some flash drives will not be seen as bootable in Legacy mode no matter what. 

Could you please reformat one of those drives using rufus and see if it works after that?

On 10/17/2023 at 6:56 PM, JonathanM said:

Could you please reformat one of those drives using rufus and see if it works after that?

 

I could but...

Bit of a problem.

Two of them ended in a bin, last remaining stick that does not work in Legacy mode is my old unraid stick which is blacklisted, so can't install unraid on it any longer.

On 10/17/2023 at 6:56 PM, JonathanM said:

Could you please reformat one of those drives using rufus and see if it works after that?

Found one of the drives. 

 

What options what you suggest to use in rufus? 

 

Boot selection? 

Syslinux? 

4.07 or 6.04?

26 minutes ago, BeersTeddy said:

What options what you suggest to use in rufus? 

 

Once that completes, extract the contents of the installation zip file to it, and run the make bootable script.

 

See if it boots properly then.

53 minutes ago, JonathanM said:

 

Once that completes, extract the contents of the installation zip file to it, and run the make bootable script.

 

See if it boots properly then.

 

Nope, nothing changed. System refuses to boot from this stick in Legacy mode.
UEFI works just fine

Just now, BeersTeddy said:

 

Nope, nothing changed. System refuses to boot from this stick in Legacy mode.
UEFI works just fine

In legacy mode, does the motherboard have various USB boot options? Some sticks show up as USB removable devices, some as USB hard drives, it can be hard to figure out the right BIOS options to successfully boot. USB compatibility options in the BIOS can come into play as well.

 

Also, try the separate boot device menu, some BIOS use the F8 key, some require you to get into the first part of BIOS setup and offer up a "one time boot" option. If that works, chances are you can find a combo of BIOS options that will allow success with a normal boot.

20 minutes ago, JonathanM said:

In legacy mode, does the motherboard have various USB boot options? Some sticks show up as USB removable devices, some as USB hard drives, it can be hard to figure out the right BIOS options to successfully boot. USB compatibility options in the BIOS can come into play as well.

 

Also, try the separate boot device menu, some BIOS use the F8 key, some require you to get into the first part of BIOS setup and offer up a "one time boot" option. If that works, chances are you can find a combo of BIOS options that will allow success with a normal boot.

It does have some option but not so much really.

Usb stick doesn't seems to be properly recognised in legacy mode as there is no brand/name displayed as usual.

 

This must be something to do with usb sticks themselves as the other ones work just fine.

 

I've checked every single setting but nothing helped to start it in Legacy mode.

Booting in UEFI works just fine