UEFI based systems are becoming more common and it's expected at some time that newer UEFI based system doesn't contain CSM to support legacy bios mode at all 1).
To accommodate this, it's necessary for OpenWrt build system to generate UEFI bootable images.
There are pending commits related to add UEFI bootable OpenWrt under Jow staging repository.
The commits necessary to build uefi bootable OpenWrt image are as follows.
tools: add libopt host build add sgdisk host build Generate EFI grub images for x86 platforms x86: fix bios mkimage during efi image generation
To build the image, checkout jow-staging repository, i.e.
$ git remote add jow-staging https://git.openwrt.org/openwrt/staging/jow.git $ git fetch jow-staging $ git checkout -b uefi-capable --track origin/master # so that you can rebase easily $ git merge jow-staging
After merging the branch or checking out jow-staging repository, run
Go to Target Images and make sure that Build EFI grub images option is checked.
Select additional packages as necessary and finally save changes and exit menuconfig.
make as usual to build the image.
The resulting image will be available as
bin/targets/x86/64/openwrt-x86-64-uefi-gpt-ext4.img.gz, which can be written to disk after decompression.
The repository contains changes based on Jow-staging branch to generate secure boot capable image
The related packages feed repository contains stuffs needed to sign efi binaries, i.e. gnu-efi and sbsigntool and stuffs to manipulate efi variables, i.e. efivar, efibootmgr, and efitools.
# Add the development git repository $ git remote add devrepo https://github.com/alive4ever/openwrt $ git fetch devrepo $ git checkout feature-uefi-secure-boot # Configure the corresponding package repository $ echo 'src-git packages https://github.com/alive4ever/packages;feature-uefi-secure-boot' > ./feeds.conf $ ./scripts/feeds clean $ ./scripts/feeds update packages $ ./scripts/feeds update -i $ ./scripts/feeds install -a # Now, configure the build system # Select x86 as Target, x86_64 as Subtarget # make sure to select 'Sign EFI executable binaries' under 'Target Images' # UEFI related tools are available under Utilities section, # which consist of efitools, efibootmgr, efivar, and sbsigntool $ make menuconfig # The certificate and key need to be generated # to perform uefi binary signing $ OLD_UMASK=$(umask) $ umask 077 $ openssl req -new -x509 -sha256 \ -days 90 -out ./db.crt \ -subj '/CN=secure boot signing certificate' \ -newkey rsa:2048 -nodes \ -keyout ./db.key $ umask $OLD_UMASK # run make to generate UEFI secure bootable OpenWrt image $ make
Remember to import
db.crt (which may needs to be converted into DER or other format) into
db UEFI variable to securely boot the resulting image.