[SOLVED] rescue boot change kernel cmdline

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diversity

Well-Known Member
Feb 19, 2020
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I run the latest proxmox with root on zfs

I locked myself out of the system by having added too many kernel cmdline parameters (/etc/kernel/cmdline) related to the disabling of the display.

So I tried using the rescue boot option on the most recent pve iso but it errors out stating it can not find rpool automatically.

And when I use the debug install terminal and exit into th command line interface and then zpool import -f rpool
I still can not find this cmdline file.

The question is how can I change the cmdline parameters using the rescue boot
 
diversity said:
And when I use the debug install terminal and exit into th command line interface and then zpool import -f rpool
I still can not find this cmdline file.
Click to expand...
Maybe you need to explicitly tell zpool import to mount it somewhere (else than / )? I don't know the command from memory right now.

If you manage to chroot into your installation (with bind-mounting dev, proc, sys, etc.) you can undo your changes to the kernel parameters. The procedure is a lot like https://pve.proxmox.com/wiki/Recover_From_Grub_Failure but your setup might use systemd-boot instead of GRUB and making sure the rpool in mounted somewhere usable is the trick here.
 
thank you leesteken. it did hint me more into the right direction.

I was able to use the proxmox iso debug installer which I exited to enter a shell
then I was able to update the /etc/kernel/cmdline
using the steps found below
https://forum.proxmox.com/threads/z...system-entering-rescue-mode.75122/post-334763

but then once I run the proxmox-boot-tool refresh command I get an error that it can not find grub directories and and rebooting i still get a black screen because of the kernel commandline parameters not having been updated.

Is there anything else I can try to make sure the boot process will correctly load the new kernel commandline parameters?
 
diversity said:
but then once I run the proxmox-boot-tool refresh command I get an error that it can not find grub directories and and rebooting i still get a black screen because of the kernel commandline parameters not having been updated.
Click to expand...
Did you bind-mount /dev, proc, sys, run etc. before doing the chroot? I remember having a EFI variables issue (but maybe you had a different error?) and I need to do mount -t efivarfs none /sys/firmware/efi/efivars also before the chroot.
 
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