Comment 7 for bug 694242

After a couple of quick tests with bcdedit, grub4dos and grub2win, I think the problem is that the windows bootmgr refuses to load other "Real-Mode boot sectors", like wubi (grub4dos) uses.

Windows signs just the toplevel bootmanager (shim.efi, grubx64.efi, ...) which is a PE format executable. It can't sign the files containing raw bootsectors (grldr, grldr.mbr, ...). Not even if someone is willing to pay the $99.

The only option right now, as loomy posted above, is to drop a replacement .efi file for Windows' bootmgr.efi in the EFI partition, and using the UEFI API, mark that as the default bootmgr (there can't be more bootmgrs AFAICT). And ideally the bootmgr allows the option of chain-loading the windows bootmgr (otherwise we won't have full support for all the boot scenarios Windows supports).

Am I missing something ? (honest question, I hope I am)