buki

Simple POSIX shell UKI builder

This was created primarily to avoid systemd-ukify on my own systems, but also to be more portable.

This script supports both llvm-objcopy and binutils' objcopy to build the UKI.

Dependencies

• llvm-objcopy or binutils objcopy
• any POSIX-capable shell
• A handful of basic utilities such as id, uname, stat, and cat if building with microcode.

Usage

• Build a UKI: buki build -i </path/to/initramfs> -k </path/to/kernel> -o </path/to/esp/bootx64.efi> [-c 'loglevel=4 init_on_free=1'] [-s /usr/lib/systemd/boot/efi/linuxx64.efi.stub] [...]

• Request help output: buki, buki help, any non buki build command.

Options

• -c - Specify kernel cmdline or path to file containing kernel parameters if begins with . or /. If nothing is specified, buki will default to /proc/cmdline. If passed a set of parameters directly, /tmp/bukitmp/cmdline will be created and will then be passed into objcopy.

• -i - Specify path to initramfs image.

• -k - Specify path to kernel.

• -m - Specify path to microcode image. If nothing is specified, UKI will be built without microcode. If specified, /tmp/bukitmp/buki-combined_initrd.img will be created, and will contain the concatenated microcode and the initrd, and will then be passed into objcopy.

• -o - Specify path to output the built UKI.

• -r - Specify path to os-release information. If nothing is specified, buki will default to /etc/os-release

• -s - Specify path to EFI stub file. If nothing is specified, buki will default to /usr/lib/systemd/boot/efi/march.efi.stub

Miscellaneous options

• -b - Forces UKI to be built with binutils objcopy rather than llvm-objcopy.
• -l - Forces UKI to be built with llvm-objcopy rather than binutils.

If an objcopy variant is not explicitly set, the first one found on the system will be used.

• -v - Verbose output when building a UKI

Miscellaneous options do not take an argument.

The order these options are set in does not matter.