Installation media refuses to boot in UEFI on my desktop core i7 4790 with asus MAXIMUS VII RANGER Z97 chipset motherboard bios v3503. I downloaded and checked Elementary OS 6 image several times, I tried to burn it with Etcher as recommended or Rufus, in MBR or GPT format. The created key refuses to start in UEFI mode. No matter if the secure boot is activated or not I always get the following error message : "Invalid image Failed to read header : Unsupported Failed to load image : Unsupported start_image() returned Unsupported"
I must specify that I never had this kind of problem before on this PC and that I installed several distributions in UEFI without encountering this error including ubuntu 20.04 LTS.
The only solution I found to boot on the installation key is to activate CSM (compatibility support module) in legacy mode in the bios boot options. But in this case impossible to install Elementary os in UEFI mode ...
Weird the same install key works perfectly on my other more recent desktop.