zz_proxmox_boot script, wrong action with pinned kernel version

[Moog]

Hi,
I've had to use the command

proxmox-boot-tool kernel pin 6.8.12-4-pve

due to the issues with an apparent diversion (that I've failed to fully get my head round) between the stock Linux Kernel 6.8.12, the Debian Kernel 6.8.12, the Proxmox Kernel 6.8.12 (which seems to be based on Ubuntu not Debian??) and changes in those WRT Intel's i915 open source GPU driver together with the patches to enable SRIOV. All this seems to break badly due to major API changes between 6.8.12-4 and 6.8.12-5 (which I thought was not supposed to happen, given the minor patch level version bump)

Anyway since running the command to pin the kernel anything that triggers the post-install scripts in /etc/kernel/postinstall.d seems to call the zz_proxmox_boot script. Which tries to install the latest kernel, and not the pinned one. I can't seem to uninstall the 6.8.12-5-pve kernel, (which had previously auto-installed itself, causing a lot of grief) without it wanting to remove all of Proxmox with it, even though that kernel is not in use.

To summarise:
Issue 1: The zz_proxmox_boot script and friends are referencing the latest not the pinned kernel - can anybody confirm that is the case?
Issue 2: Attempting to uninstall an unused but later kernel wants to remove all of Proxmox - is this nornal and desired behaviour?
Issue 3: Please clarify the origin of the Proxmox kernel as it's source (related to DRM) does not seem to be related to Debian or stock Linux. It's like some patches are missing or wrongly applied?? Not manage to investigate deep enough to understand so some pointers are needed.

Update:
I can see a file /etc/kernel/proxmox-boot-pin and that file is checked in bash functions, but that check is being bypassed by the way the scripts are being called, i.e. the script is bring called by something (can't work out what) with the specific kernel version.
Here is an example, triggered by an

apt autoremove

you can see it goes straight into 'setting up kernel ...'

root@dusty:~# apt autoremove                                                                                                                                               [408/1039]
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following packages will be REMOVED:
  proxmox-kernel-6.8.12-3-pve-signed
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
2 not fully installed or removed.
After this operation, 576 MB disk space will be freed.
Do you want to continue? [Y/n]
(Reading database ... 242097 files and directories currently installed.)
Removing proxmox-kernel-6.8.12-3-pve-signed (6.8.12-3) ...
Examining /etc/kernel/prerm.d.
run-parts: executing /etc/kernel/prerm.d/dkms 6.8.12-3-pve /boot/vmlinuz-6.8.12-3-pve
Examining /etc/kernel/postrm.d.
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 6.8.12-3-pve /boot/vmlinuz-6.8.12-3-pve
update-initramfs: Deleting /boot/initrd.img-6.8.12-3-pve
run-parts: executing /etc/kernel/postrm.d/proxmox-auto-removal 6.8.12-3-pve /boot/vmlinuz-6.8.12-3-pve
run-parts: executing /etc/kernel/postrm.d/zz-proxmox-boot 6.8.12-3-pve /boot/vmlinuz-6.8.12-3-pve
Re-executing '/etc/kernel/postrm.d/zz-proxmox-boot' in new private mount namespace..
No /etc/kernel/proxmox-boot-uuids found, skipping ESP sync.
run-parts: executing /etc/kernel/postrm.d/zz-systemd-boot 6.8.12-3-pve /boot/vmlinuz-6.8.12-3-pve
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 6.8.12-3-pve /boot/vmlinuz-6.8.12-3-pve
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-6.8.12-5-pve
Found initrd image: /boot/initrd.img-6.8.12-5-pve
Found linux image: /boot/vmlinuz-6.8.12-4-pve
Found initrd image: /boot/initrd.img-6.8.12-4-pve
Found linux image: /boot/vmlinuz-6.5.13-6-pve
Found initrd image: /boot/initrd.img-6.5.13-6-pve
Found linux image: /boot/vmlinuz-6.5.11-8-pve
Found initrd image: /boot/initrd.img-6.5.11-8-pve
Found memtest86+ 64bit EFI image: /boot/memtest86+x64.efi
Adding boot menu entry for UEFI Firmware Settings ...
done
Setting up proxmox-kernel-6.8.12-5-pve-signed (6.8.12-5) ...
Examining /etc/kernel/postinst.d.
run-parts: executing /etc/kernel/postinst.d/dkms 6.8.12-5-pve /boot/vmlinuz-6.8.12-5-pve
dkms: running auto installation service for kernel 6.8.12-5-pve.
dkms: autoinstall for kernel: 6.8.12-5-pve.
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 6.8.12-5-pve /boot/vmlinuz-6.8.12-5-pve
update-initramfs: Generating /boot/initrd.img-6.8.12-5-pve
mRunning hook script 'zz-proxmox-boot'..
Re-executing '/etc/kernel/postinst.d/zz-proxmox-boot' in new private mount namespace..
No /etc/kernel/proxmox-boot-uuids found, skipping ESP sync.
run-parts: executing /etc/kernel/postinst.d/proxmox-auto-removal 6.8.12-5-pve /boot/vmlinuz-6.8.12-5-pve
run-parts: executing /etc/kernel/postinst.d/zz-proxmox-boot 6.8.12-5-pve /boot/vmlinuz-6.8.12-5-pve
Re-executing '/etc/kernel/postinst.d/zz-proxmox-boot' in new private mount namespace..
No /etc/kernel/proxmox-boot-uuids found, skipping ESP sync.
run-parts: executing /etc/kernel/postinst.d/zz-systemd-boot 6.8.12-5-pve /boot/vmlinuz-6.8.12-5-pve
run-parts: executing /etc/kernel/postinst.d/zz-update-grub 6.8.12-5-pve /boot/vmlinuz-6.8.12-5-pve
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-6.8.12-5-pve
Found initrd image: /boot/initrd.img-6.8.12-5-pve
Found linux image: /boot/vmlinuz-6.8.12-4-pve
Found initrd image: /boot/initrd.img-6.8.12-4-pve
Found linux image: /boot/vmlinuz-6.5.13-6-pve
Found initrd image: /boot/initrd.img-6.5.13-6-pve
Found linux image: /boot/vmlinuz-6.5.11-8-pve
Found initrd image: /boot/initrd.img-6.5.11-8-pve
Found memtest86+ 64bit EFI image: /boot/memtest86+x64.efi
Adding boot menu entry for UEFI Firmware Settings ...
done
Setting up proxmox-kernel-6.8 (6.8.12-5) ...