HP Z620 boot from nvme issue

Special Topics NVMe Support for old Systems
2

Mods apart… as you say latest bios doesn’t need it and already have NVMe support.
(UEFI x64 OS)

Step 4

[HowTo] Get full NVMe Support for all Systems with an AMI UEFI BIOS - Special Topics / NVMe Support for old Systems - Win-Raid Forum (level1techs.com)

HP Z Turbo G1
Solved: Is HP Z Turbo Drive G2 compatible with the Z620 workstation? - HP Support Community - 5616398