I'm not aware of any plans to release a new version of the 8.0 installer. What you can do is:I have just hit this issue also today on an oldish Supermicro MB, is there a v8 installer that works yet?
I am using a Powered R820 and have the same problem. Had to install 7.4 and upgrade.Working with a T410 also and just discovered this bug today. Will try the upgrade method @ylavi
When trying to install 7.4 and upgrade, I ran into a different issue, but was able to successfully install 8.0 by following the debug shell method outlined earlier in the thread.I am using a Powered R820 and have the same problem. Had to install 7.4 and upgrade.
wget https://enterprise.proxmox.com/debian/proxmox-release-bookworm.gpg -O /etc/apt/trusted.gpg.d/proxmox-release-bookworm.gpg
apt update
apt upgrade
apt install systemd-boot
proxmox-boot-tool init /dev/sda2
proxmox-boot-tool init /dev/sdb2
proxmox-boot-tool reinit
proxmox-boot-tool refresh