I've been playing around with several virtual machines for some tests I'm doing - 64-bit versions of Windows Vista (SP1), Windows 7 (SP1) and Windows 8.1 installed in native UEFI mode. So what do the following files (on the EFI System Partition) actually do?
On the Windows Vista system I was able to boot without bootmgr.efi - it wouldn't boot without bootmgfw.efi though. Interestingly the Vista install did not actually appear to have a firmware boot loader at all - there was no \EFI\boot\bootx64.efi file. VMWare Player appears to boot the Vista installation via the Windows Boot Manager option in the UEFI Boot Manager menu (accessible by pressing the Esc key during power up - I added bios.bootDelay="5000" to the config file so that I actually had enough time to press it!!!)
I don't really get many aspects of this UEFI!
A simplified explanation of the Windows UEFI boot process would be really helpful. There are various discussions out there that imply that bootmgfw.efi is part of the process - didn't seem to be on two out of my three test systems! Or is it perhaps somehow required for hibernate to work properly?