Change from UEFI to Legacy Bios?

[sgtpepperaut]

hi fellow Proxmoxers,

It seems my old DELL server will not work with a GPU passthrough in UEFI mode. I have successfully configured the passthrough in Legacy Bios (on the host) but on a new Proxmox install on the same machine with UEFI I cant get it to work. In fact the host sometimes freezes and straight up crashes.

My question is how can I change an existing proxmox install from EFI to legacy boot? I am not talking about settings the bios options but rather how to change to GRUB on the running proxmox host...

Thanks for any help or pointers.

 

[aaron]

My question is how can I change an existing proxmox install from EFI to legacy boot?

Theoretically possible, but a risky operation, even if you know what you do. Definitely something that should be tested/trained in a VM before.

If you do not have that much on it, a reinstall with backups of the guests an important config files might be the easier solution.

 

[sgtpepperaut]

Im just clicking buttons and pasting script in the shell.. so... reinstall & restore it is

but on a related note.... Can the boot mode have an affect on PCI passthrough or do you think its more likely that something else is going on?

Thanks and take care

 

[aaron]

but on a related note.... Can the boot mode have an affect on PCI passthrough or do you think its more likely that something else is going on?

I don't have enough experience with PCI passthrough to answer that :-/.

but on a new Proxmox install on the same machine with UEFI I cant get it to work. In fact the host sometimes freezes and straight up crashes

You did not exactly explain how far you got in UEFI mode. Does the device that you pass through have its own IOMMU group for itself?