I have a number of these desktops to build at work. We currently use Foreman with PXE network boot to build custom Ubuntu desktops.
I have disabled Secure Boot.
I have disabled Sure start secure boot keys protection and Enhanced HP firmware runtime intrusion.
I have disabled HP Sure Recover
I have disabled DMA protection
But I cannot find the option to Legacy boot. When I boot and select the network interface it just goes to a blank screen and returns to the BIOS. I cannot use physical boot media such as a USB or CD as this has not been setup on our Foreman.
I'm sorry, but HP does not provide support for Linux distros.
IF you replace the preloaded Windows OS with a Linux distro, or add a Linux distro, then you assume full responsibility for maintaining that -- including solving any problems with booting the other OS and/or installing the other OS.
Modern PCs with UEFI, instead of the older BIOS, are especially difficult to install because you have to go into the UEFI settings and make several changes before you can even boot from a USB stick -- and we are unable to assist in that work.
Your best bet for support now is to contact the support forum of the distro you are using.
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