We have a project within our company to refresh PCs to the latest build of Windows 10 and enable Bitlocker. It captures the user state/network/Windows settings within Windows 10 to a state migration point, and then reboot into Windows PE, format the disks, enable secure boot and then format again to GPT and restart to Windows PE.
Our TS works completely fine when the computer was imaged originally using UEFI. However we have some PCs in our company that were imaged on legacy boot (we use mostly HP 800 G3-G6 devices) and when the steps to convert BIOS to UEFI, it reboots and then attempts to PXE, and then ends up with "No Operating system found". If I turn secure boot off, the TS continues normally in legacy boot. At the moment we are considering just wiping these through PXE boot but that requires us to be onsite and we have 1000+ PCs to do this for.
I've attached a copy of my task sequence steps and a copy of the task sequence for reference. I would really appreciate any advice as I am out of ideas.