Looking at the Troubleshooting part of https://pve.proxmox.com/wiki/Upgrade_from_6.x_to_7.0 before doing the upgrade, as having an older BIOS-based install on ZFS, I understand I need to https://pve.proxmox.com/wiki/ZFS:_Switch_Legacy-Boot_to_Proxmox_Boot_Tool first. However:
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