Hello,
My organization is going through a Windows 7 to 10 upgrade and I am running into an issue with the Z420. I have about 100 of these throughout my environment and I've seen this issue on about 10 of them so far. I use SCCM OSD to deploy the Win10 image, and in the task sequence I am editing BIOS settings, the major changes are disabling Legacy and enabling UEFI and Secure boot. After the BIOS changes are made, the machine is then stuck in a reboot loop with no video. The only fix is to press the CMOS button on the motherboard. The machine is using the most current BIOS J61 3.91. If I enable UEFI and Secure Boot manually, I am able to image to Windows 10 no problem it's only an issue when SCCM changes the settings. I'm using HP's BIOS config utility to make the change.
Any ideas?