Create UEFI boot USB
This article explains how to create an UEFI boot USB with parted and gummiboot.
In this example we will use `/dev/sdX`. This will be different depending on your system.
Create GPT boot partition
Install 'parted'
apk add parted
Create a single UEFI boot partitions.
parted --script /dev/sdX mklabel gpt
{{{1}}}
parted --script /dev/sdX set 1 boot on
Create fat32 filesystem
Create a fat32 system with the name `Alpine`.
mkfs.vfat -n Alpine /dev/sdX1
Copy content of ISO image to filesystem
It is possible to mount the iso image and copy files with `cp` or `rsync` and it is also possible to use `7z` to extract content from the iso. In this example I will use the `uniso` utility from alpine-conf package.
mount -t vfat /dev/sdX1 /mnt
cd /mnt && uniso < /path/to/alpine-3.4.0-x86_64.iso
Copy gummiboot efi binary
UEFI will look for a EFI/bootx64.efi as a fallback efi loader. We copy gummibootx64.efi to this location.
mkdir -p /mnt/EFI/Boot
apk add gummiboot
cp /usr/lib/gummiboot/gummibootx64.efi /mnt/EFI/Boot/bootx64.efi
Create configuration files for boot loader
We need create some configuration files for gummiboot.
mkdir -p EFI/loader/entries
Contents of EFI/loader/loader.conf
The options are taken from boot/syslinux/syslinux.cfg
Contents of EFI/loader/entries/grsec.conf