HW Watchdog Info

Most guides/posts online mention that the watchdog needs to be disabled for any 3rd party OS to run, however the HW watchdog (IT87 WDT) is already supported in linux, so it just needs to be set up to feed it on the same interval as UGOS.

Pulling the disk off the device, the second partition is the squashfs used as the base for the overlay FS. In this case, the watchdog is setup to be fed in systemd, and the config for that is in /etc/systemd/system.conf:

[Manager]
RuntimeWatchdogSec=120
RuntimeWatchdogPreSec=off
RebootWatchdogSec=2min
KExecWatchdogSec=off
WatchdogDevice=/dev/watchdog
DefaultTimeoutStopSec=30s

So for any other OS, we'll need to confirm that the watchdog is found and is at /dev/watchdog, then this same config should work

Updating Proxmox Install ISO

sudo unsquashfs pve-base.squashfs
# add system.conf
sudo mksquashfs squashfs-root pve-base-new.squashfs -comp zstd -Xcompression-level 19 -b 262144

Script to update ISO

#!/usr/bin/env bash
ISO=$1
FILE=$2
DEST=$3

UUID=$(xorriso -dev $ISO -report_system_area cmd 2>/dev/null | sed -nr 's/-volume_date uuid .([0-9]+)./\1/p')
cp $ISO $ISO.bak
if ! xorriso -boot_image any keep -volume_date uuid $UUID -dev $ISO -update $FILE $DEST; then
        echo "error, restoring backup"
        mv $ISO.bak $ISO
fi

./update_proxmox_iso.sh proxmox-ve_8.2-1.iso pve-base-new.squashfs /pve-base.squashfs