update-grub not working

[SelfhostedPro]

Hey, sorry if this is the wrong place but feel free to point me in the right direction. I've got vanilla-os installed on a microsoft surface pro 7 and I'm working on installing surface-linux for which I assume I need to do in abroot shell since it's a different kernel. I'm able to get through to the point where it tries installing the kernel and tries to upgrade grub to point at it. This is needed for quite a few pieces of hardware (including the touchscreen) to work.

The specific error I'm getting is the following:

/usr/sbin/grub-probe: error: failed to get canonical path of `overlay'.

Here are the full logs: https://pastebin.com/28YYBWWy

I'm able to use the computer in the meantime but would like for stuff like my touchscreen and cooling to work correctly. If there's any troubleshooting you'd like me to do or workarounds to try, please let me know. I also understand if this isn't something you'd like to support.

[SelfhostedPro]

Changed the failing post install script (/etc/kernel/postinst.d/zz-update-grub)to the following:

#! /bin/sh
set -e
#set -- $DEB_MAINT_PARAMS
echo $DEB_MAINT_PARAMS
#mode="${1#\'}"
#mode="${mode%\'}"
#B
#case $0:$mode in
    # Only run on postinst configure and postrm remove, to avoid wasting
    # time by calling update-grub multiple times on upgrade and removal.
    # Also run if we have no DEB_MAINT_PARAMS, in order to work with old
    # kernel packages.
#    */postinst.d/*:|*/postinst.d/*:configure|*/postrm.d/*:|*/postrm.d/*:remove)
#       if [ -e /boot/grub/grub.cfg ]; then
#               exec update-grub
#       fi
#       ;;
#esac
#exec update-grub
exit 0

then manually ran update-grub and it seems to be working.