Experiments with my new laptop, Linux and UEFI
In this context I use 'critical' to indicate the parts which sometimes give Linux difficulty, such as the graphic controller (ATI/AMD Radeon in this case), wi-fi adapter (Atheros) and such. Installation was absolutely routine, exactly as I have described several times before on several other UEFI systems.
I left Secure Boot enabled, and I had no problem booting the Live USB image. Fedora installed its own signed "shim" file, so the installed image also boots just fine with UEFI Secure Boot enabled — and, of course, also with Secure Boot disabled, duh.
During the installation, it added Fedora to the UEFI boot list and it modified the UEFI boot sequence to place Fedora first; when I rebooted after installation, it booted up Grub (and then Fedora), exactly as it "should". I was extremely pleased and impressed with this, and I started to think that perhaps HP had improved its UEFI BIOS operation (although it seems I was wrong).