How to add UEFI image boot option in BCDedit?

Question

I just installed FreeBSD on a GPT partition. On which is also installed Windows 8.1 and it's EFI partition with Windows Boot Manager. The FreeBSD installer auto-added another EFI partition with it's bootloader. I get my hands on it ('BOOTx64.efi') but now I have no idea how to include into the Windows Boot manager. I mean I can easily drop it into it's EFI partition but the problem is how to link it with BCDedit. I added a FWBOOTMGR and then I don't know what to do. There is even no documentation on what is this.

Any ideas?

Answer 1

Boot sequence for UEFI is:

1. firmware boot manager

2. first boot candidate from NVRAM boot entries

In NVRAM there is a variable "bootOrder" which holds an ordered list of NVRAM boot variables (analogue is Windows "displayorder").

Using firmware setup you can change order of boot variables in "bootOrder".

Every OS installation (Windows, Linux, BSD etc.) creates a corresponding boot variable for itself and puts it in bootOrder list (usually in first position).

All OS boot managers/loaders are stored on "EFI System Partition" in corresponding subfolder ( \EFI\Microsoft, EFI\ubuntu etc.)

See rEFInd boot manager which can boot (chain load) any OS on UEFI.

See BootNext tool which can boot any OS from Windows 7/8/10.

See a more detailed explanation on EFI NVRAM variables.