At first I encountered https://kb.vmware.com/s/article/83063 the missing crypto64.efi problem - just because I ran a simple update via vcenter.
After remediating that with a manual upgrade of the host, the next issue was, that - I do not know, which upgrade did it - the iSCSI-name of my iSCSI software adapter was changed to something totally new. That broke all volumes and VMs on those volumes, which were LUNs on the iSCSI-adapter. To solve this problem I renamed the adapter back to it's old name. But that did not help - unless I restartet the host, because I could not restart the iSCSI stack on the host.
All in all a huge and unnecessary waste of my time.
