fix efistub bootloader to use backslashes

[h8d13]

As seen in wiki example:
https://wiki.archlinux.org/title/EFI_boot_stub#efibootmgr

efibootmgr --create --disk /dev/sdX --part Y --label "Arch Linux" --loader /vmlinuz-linux \
--unicode 'root=block_device_identifier rw initrd=\initramfs-linux.img'

Was just wondering why EFIstub never worked to boot and found this :)

#1431 #2684

[codefiles]

This does not fix anything, see the note at the bottom of Unified Extensible Firmware Interface#efibootmgr.

Edit: The note is not applicable to kernel parameters.

[h8d13]

This does not fix anything, see the note at the bottom of Unified Extensible Firmware Interface#efibootmgr.

Right so try without the patch and then with it? I do not think you had the time to do so ? Are you actively testing changes ? Also did you look at linked issues ?

Like we have never seen firmware quirks, and shouldn't respect the actual specification of provided example (because explicit is better than implicit :) ?

The conversion works for --loader not --unicode that goes straight to the firmware as is (hence the 'content here'. Have a good rest of your sunday, Hade

[codefiles]

You are correct, the note I mentioned does not apply to the kernel parameters like initrd.

Relevant sections of the ArchWiki that support this change:

• https://wiki.archlinux.org/title/Kernel_parameters#Parameter_list
• https://wiki.archlinux.org/title/EFI_boot_stub#Booting_an_EFI_boot_stub

I have caught this before in the past but never submitted changes because I misunderstood the note. I also tested this same thing in the past but could not get it to work in my test environment.

[h8d13]

You can also also see it directly here: https://github.com/rhboot/efibootmgr/blob/main/src/efi.c#L330-L361
Which converts UTF-8 → UCS-2 directly https://uefi.org/specs/UEFI/2.10/13_Protocols_Media_Access.html#file-names

[codefiles]

Left some comments that are extremely minor. Good to be merged as is.