HP Sure Start won't let me enable legacy support in BIOS

[r4a5a88]

Hello Community,

I am an Admin ans am trying to install ourWindows 10  boot image onto a HP desktop PC.
the PC is a brand new elitedesk 800 g5. The Problem is whenever I set the BIOS to "legacy support enable and Secure boot disable" I get a message on the next startup with 4 digits and when I enter the digits secure boot is enabled again.

My bios version is R01 Ver 02.04.02

Online, you find a lot of videos on how to set it to legacy boot butno one had that 4 digit message. I already removed the battery for 2 minutes to reset bios but that did not change a thing.

Do you know how to solve it ?

[r4a5a88 · Accepted solution]

I found the problem TPI. A thing in BIOS to protect from intrusion

You have to diable it to change the 4 digit thing