Hi, hope I’m not too late to the party (it might at least help somebody else) but I had a similar issue with T630. There was some sort of lock in the BIOS (which was also in German) and the HA would not boot properly (however I was able to boot Ubuntu). In my case the solution was to re-flash the BIOS with the latest version from the HP website. There are instruction on how to do it, but as far as I remember I copied the file on a USB stick put it into the client and chose to re-flash the BIOS from a BIOS menu. Just be patient, it took somewhere around 10+ minutes if I remember correctly. I thought I bricked the damn thing, but then suddenly it restarted and started the boot sequence. But since then (it’s been like 2 years already) I never has a single problem with the client. It’s quiet and runs flawlessly. The operating temperatures fall within a ballpark of 35-45 degrees.