Created Freitag 01 November 2019
Usage hints
Check BIOS mode
Linux
On kernel >4. If the file does not exist, then the system was not bootet in UEFI mode.
$ cat /sys/firmware/efi/fw_platform_size
macOS
<2008 Macs: IA32 EFI 1.x
>=2008 Macs: x86_64 EFI 1.x
Apple's EFI implementation is not fully compliant witn the
$ ioreg -l -p IODeviceTree | grep firmware-abi
Windows
Start msinfo32.exe.
Values of "System Type" and "BIOS mode":
64bit Win + UEFI 64: System Type: x64-based PC, BIOS mode: UEFI
32bit Win + UEFI 32: System Type: x86-based PC, BIOS mode: UEFI
-> Win 64 does not support booting on a UEFI 32.
EFI Boot methods
EFISTUB
Kernel compiled with EFISTUB to run directly from EFI ESP placed in
Find location of ESP (Ubuntu: /boot/efi) :
# findmnt efi
Store linux initrd and kernel relativly to ESP:
<esp>/EFI/ubuntu/initrd.img-xxx
<esp>/EFI/ubuntu/vmlinux-xxx
Create boot entry:
# efibootmgr --disk /dev/sdX --part Y --create --label "Arch Linux" --loader /vmlinuz-linux --unicode 'root=<PARTUUID=XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX> rw initrd=<\initrd.img-xxx>' --verbose
X: disk number
Y: partition number
Set boot order:
# efibootmgr --bootorder XXXX,XXXX --verbose
XXXX: Number of boot entry
Boot manager
Classical boot manager which has to support EFI:
Grub, REFInd, ...
Add a boot option
- The disk containing the EFI system partition (ESP). E.g.: /dev/sda, /dev/nvme0n1.
- The partition number of the ESP on that disk. The Y in /dev/sdaY or /dev/nvme0n1pY.
- The path to the EFI application (relative to the root of the ESP)
# efibootmgr --create --disk /dev/sda --part 1 --loader /EFI/refind/refind_x64.efi --label "rEFInd Boot Manager" --verbose
Tools
efibootmgr
Homepage
Tool to manipulate UEFI Firmware Boot Manager Settings like boot order, boot devices, ...