PVE8to9 fail

[mattps]

Hi Forum,

Struggling here and need some guidance. I have successfully upgraded one of my PVE hosts to version 9 and attempted to upgrade my second host, however something went wrong and it crashed mid upgrade. Now when I try to boot I get "Welcome to GRUB" and the server reboots.

I'm trying to repair the bootloader but can't even boot from the 8.4 ISO. I've tried with 3 USB sticks, using Etcher and Rufus but they all fail to boot - on any of my devices. Any suggestions?

Pulling my hair out here!

 

[YG-Infra]

Hi,

I would separate the issue into two parts:

1. the node itself is stuck very early at “Welcome to GRUB”
2. the rescue USB does not boot properly, at least on the affected host

Since you already tried multiple USB sticks/tools, I would first verify the ISO checksum and write the ISO again in DD/raw mode. Also check the server firmware settings: Secure Boot off, correct UEFI/legacy boot mode, try both USB boot entries if shown, and try another USB port.

If possible, also test a Debian live/rescue ISO. That would show whether this is specific to the Proxmox ISO or a more general USB boot/firmware issue.

Once you can boot a rescue environment, don’t reinstall immediately. First check the disk and boot layout:

lsblk -f
efibootmgr -v

The correct repair steps depend on whether the host uses GRUB, systemd-boot/proxmox-boot-tool, ZFS, LVM, UEFI, etc.

Since the crash happened during the 8 → 9 upgrade, after mounting the installed system and chrooting into it, you will probably also need to finish the interrupted package configuration:

dpkg --configure -a
apt --fix-broken install
apt full-upgrade

Afterwards, running the upgrade checker again would also be useful:

pve8to9

But I would not run grub-install blindly before knowing the layout.

Please post the output of:

lsblk -f
efibootmgr -v

and, after mounting the installed root filesystem, the installed system’s fstab, for example:

cat /mnt/etc/fstab

from a rescue/live environment.