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UEFI and BIOS support on Alpine
UEFI replaces the BIOS firmware interface originally present in all IBM PC-compatible personal computers, early modern computer's UEFI firmware implementations provide legacy support for BIOS services.
UBOOT are a boot process for embebed devices and minidevices, pretty mostly present at the single board computers and some phones.
The complete information is at the alpine/requirementes.md booting section.
This document is the most up to date, the oficial wiki page from Alpine is currently outdated, please check the Licensing clarifications section of this document for any copyright issue.
About BIOS and UEFI
In the old days, BIOS(for Basic Input Output System) was how computers booted from the 1980s onwards. But now in newer hardware for devices, servers, laptops and desktops computers the UEFI(for Unified Extensible Firmware Interface) defines a software interface between an operating system and platform firmware into the vendor hardware.
Note Consult more at ../alpine/alpine-boot-uefi-bios.md
Where i will find BIOS based devices
Any computer until 2010 or older will only have a BIOS system to boot. Any IBM pc computer wil have also BIOS and any coputer until 2014 will have almost UEFI legacy support to boot like BIOS.
On those system marked as older harware you will need a MBR based partition table only, and cannot use GTP partitions.
Where i will find UEFI based devices
Any computer since 2014 will have UEFI for sure, but 2013/2014 ones wil have buggy UEFI implementations. Its recommended to avoid any computer from 2013 or 2014, and if you have a BIOS+UEFI then enabled the legacy mode.
Also any Vendor marked computer bqased on x86 or 64bit, or any 64bit computer will have UEFI, specially those that are parnership with Mocosoft.
Alpine UEFI support
Currently are enought for boot most systems, not all the architectures are complete supported. Since 3.16 Alpine is able to setup UEFI only with grub install flavor, syslinux can able to install UEFI but only with few devices. Some users need to setup non grub to work.
Warning Mayor information is at alpine/requirementes.md booting section document.
Minimum Alpine partition scheme
Alpine Linux requires a root partition, but on UEFI systems an EFI, a "System Partition" is also required. So a minimun of 3 partitions will be required.
UEFI booting does not involve any "boot" flag, that's it's a need only for BIOS booting.
A BIOS "boot partition for EFI" is only required when using GRUB for BIOS booting from a GPT disk. The partition has nothing to do and it must not be formatted with a file system or mounted.
UEFI/GPT minimal layout
| Mount point | Partition | Partition type Purpose | Recommended minimum size | Formats |
|---|---|---|---|---|
| /boot or /efi | /dev/sda1 | GPT UEFI Boot partition | 260 MiB | ext2/3/4 |
| / | /dev/sda2 | Alpine Linux root system OS | 1–32 GiB | btreefs,ext2/3/4,xfs |
| none | /dev/sda3 | Linux swap memory | 1-2Gb | swap |
BIOS/MBR minimal layout
| Mount point | Partition | Partition type Purpose | Recommended minimum size | Formats |
|---|---|---|---|---|
| /boot | /dev/sda1 | Boot partition (optional) | 100 MiB | btreefs,ext2/3/4,xfs |
| / | /dev/sda2 | Alpine Linux root system OS | 1–32 GiB | btreefs,ext2/3/4,xfs |
| none | /dev/sda3 | Linux swap memory | 1-2Gb | swap |
BIOS/GPT minimal layout
| Mount point | Partition | Partition type Purpose | Recommended minimum size | Formats |
|---|---|---|---|---|
| None | /dev/sda1 | GPT BIOS boot partition | 20 MiB | ext2/ext3 |
| / | /dev/sda2 | Alpine Linux root system OS | 1–32 GiB | btreefs,ext2/3/4,xfs |
| none | /dev/sda3 | Linux swap memory | 1-2Gb | swap |
Secure Boot Support
Support for secure boot are since Alpine 3.15
realized by package secureboot-hook and efi-mkkeys, this means
that you must load a own signed kernel and put a own certificate to the UEFI/BIOS.
Due the "Unsigned code curse", Alpine linux EFI System Partition are not the complete overall of the Secure Boot, it's just the need minimal infrastructure to property boot it!
Is recommended to disable Secure Boot. Alpine has no own certificate, the process only permit to load your own certificate to your UEFI BIOS, it does not have a certificate which some other Linux distributions (mostly enterprise-related) have.
Warning for more information about please check alpine/alpine-boot-uefi-bios.md Secure Boot section document.
Overall notes and conclusions
Currently Alpine UEFI and Secure Boot are very basic and enought to work, but are just implementations and not official UEFI listed so Secure Boot must be disabled at first install.
BIOS computers or UEFI computers with Compatibility Support BIOS are the easiest and most reliable way to install, they do not need the new EFI partition to boot nor new special files.
Licensing clarifications
This document were started at oficial Alpine wiki, but was over 22:22, 18 August 2019, so the wiki licence was pretty simple "are owned by creator" so cannot be redistribute without the following license:
CC BY-NC-SA: the project allows reusers to distribute, remix, adapt, and build upon the material in any medium or format for noncommercial purposes only, and only so long as attribution is given to the creators involved. If you remix, adapt, or build upon the material, you must license the modified material under identical terms, includes the following elements:
- BY – Credit must be given to the creator of each content respectivelly, starting at the first contributor.
- NC – Only noncommercial uses of the work are permitted, with exceptions if you fill an issue here!
- SA – Adaptations must be shared under the same terms, you must obey this terms and do not change it.
Complete license at: https://codeberg.org/alpine/alpine-wiki/src/branch/main#license
Original started at: https://wiki.alpinelinux.org/w/index.php?title=Alpine_and_UEFI&oldid=16188