[SOLVED] How to use Proxmox recovery mode to roll back mistakes

Jungle153

New Member
Feb 19, 2025
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Hi Folks,

I have made a bit of a mess of my proxmox setup and would rather not reinstall everything again if possible. I would like to know how to edit a PCIE pass through that has broken my system.

What happened: I was tinkering with my Home Assistant and passed through a raw device in the form of the onboard wireless nic. When I rebooted HAOS I was immediately locked out of the GUI.

I have tried logging in locally on the server however I have run into the next issue. I am greeted with the login screen however when I type in my user name and hit enter one of 2 things will happen. Either the password field will not show and then 10 seconds or so later the screen goes black and then returns to the normal login screen or I get the password field enter my password and then the same happens 10secs of nothing followed by black screen and return to login screen.

During the boot sequence I can select previous versions and the same happens for each. However I can select the recovery mode and log in as expected. Now comes the next problem...

I can't see any of the ZFS pools, including local-lvm or local where all the containers and VM files are located. So cannot edit the VM config and remove the pass through.

Additionally, when I allow the boot process to complete as normal, as well as the login issue, I lose all the USB 2 ports on the motherboard. USB 3 function normally.

The problem I think I have created by passing through the wireless nic is the IOMMU group includes usb 2, among others.

I would very much like some help to reverse the issue I have created please. I have not attempted to import the zfs pools into the recovery mode as I don't want them to disappear from the maion boot and make things worse... If that's possible.

System is AMD based on a Gigabyte A520I AC motherboard. Happy to provide further information if needed.

edit: I use a 2.5gb PCIE nic rather than the onboard Gb nic. I had previously pinned the 2.5gb nic so that it's name would not change if I add anymore PCIE cards (This was a lesson learned last time I was messing around and adding the new nic and broke everything.)

Cheers
Jungle
 
Last edited:
Easy way to prevent VMs with PCI(e) passthrough from automatically starting is to temporarily disable IOMMU/VT-d in the BIOS or even simpler is to edit the boot command line in the boot menu once (by pressing e) and adding amd_iommu=off and/or intel_iommu=off (depending on your CPU). Proxmox will boot normally but all those VMs fail to start before they claim the devices. Then you can fix the VM configurations.
 
Easy way to prevent VMs with PCI(e) passthrough from automatically starting is to temporarily disable IOMMU/VT-d in the BIOS or even simpler is to edit the boot command line in the boot menu once (by pressing e) and adding amd_iommu=off and/or intel_iommu=off (depending on your CPU). Proxmox will boot normally but all those VMs fail to start before they claim the devices. Then you can fix the VM configurations.

Thank you so much. That worked perfectly and I'm now back up and running. You've saved me many hours of setting everything back up again and most importantly you've saved me from the wrath of a 13 year old with out access to their Jellyfin account.