Date: Wed, 15 Jan 2025 05:49:43 +0000 (GMT)
From: Mark Hills <mark@xwax.org>
To: ~alpine/users@lists.alpinelinux.org
Subject: Solutions for EFI booting / copying kernels
Message-ID: <8f3899df-71b7-6562-7688-7bebc6ac1f94@xwax.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii

I have a few Alpine systems which use EFI to boot with syslinux.

I'd like to improve this setup.

The kernel+initramfs are copied to /efi, where syslinux finds them.

Invariably, after "apk upgrade" I forget to do this copy, resulting in a 
system that won't boot.

I tried to automate it with kernel-hooks.d; this is run after kernel 
upgrades:

  $ cat /etc/kernel-hooks.d/efi.hook
  cp --verbose --update \
        /boot/vmlinuz-* /boot/initramfs-* \
        /efi

But is buggy because it runs before initramfs is updated (details below.)

My own "trigger" on apk upgrade could work, but there's no path I can add 
one to (they must originate from a package)

Regular syslinux (on MBR) reads the ext4 /boot partition; the EFI variant 
cannot do this, and otherwise that would seem to be the best solution. 
Perhaps GRUB can, but I like syslinux as it feels straightforward (unlike 
GRUB)

-- 
Mark


$ cat /efi/EFI/syslinux/syslinux.cfg
TIMEOUT 20
PROMPT 1
DEFAULT lts

LABEL lts
  LINUX /vmlinuz-lts
  INITRD /initramfs-lts
  APPEND root=/dev/vg0/root modules=ext4 quiet


$ ls /efi
EFI  initramfs-lts  vmlinuz-lts


$ doas apk upgrade
[...]
(13/17) Upgrading linux-lts (6.6.68-r0 -> 6.6.71-r0)
(14/17) Upgrading linux-lts-doc (6.6.68-r0 -> 6.6.71-r0)
(15/17) Upgrading linux-lts-dev (6.6.68-r0 -> 6.6.71-r0)
[...]
Executing busybox-1.36.1-r29.trigger
Executing kmod-32-r0.trigger
Executing kernel-hooks-0.2-r0.trigger
kernel-hooks: executing hook 20-akms.hook (lts, 6.6.71-0, 6.6.68-0)
akms: Uninstalling module acpi_call/1.2.2-r0 from kernel 6.6.68-0-lts
akms: Building module acpi_call/1.2.2-r0 for kernel 6.6.71-0-lts
make: Entering directory '/usr/src/linux-headers-6.6.71-0-lts'
  CC [M]  /var/lib/akms/6.6.71-0-lts/acpi_call/1.2.2-r0/build/acpi_call.o
  MODPOST /var/lib/akms/6.6.71-0-lts/acpi_call/1.2.2-r0/build/Module.symvers
  CC [M]  /var/lib/akms/6.6.71-0-lts/acpi_call/1.2.2-r0/build/acpi_call.mod.o
  LD [M]  /var/lib/akms/6.6.71-0-lts/acpi_call/1.2.2-r0/build/acpi_call.ko
make: Leaving directory '/usr/src/linux-headers-6.6.71-0-lts'
akms: Installing module acpi_call 1.2.2-r0 for kernel 6.6.71-0-lts
akms: Module acpi_call/1.2.2-r0 for 6.6.71-0-lts installed successfully
kernel-hooks: executing hook efi.hook (lts, 6.6.71-0, 6.6.68-0)
+ cp --verbose --update /boot/vmlinuz-lts /boot/initramfs-lts /efi
'/boot/vmlinuz-lts' -> '/efi/vmlinuz-lts'
Executing akms-0.2.1-r0.trigger
Executing ca-certificates-20241121-r1.trigger
Executing gtk-update-icon-cache-3.24.43-r0.trigger
Executing desktop-file-utils-0.27-r0.trigger
Executing mkinitfs-3.10.1-r0.trigger
==> initramfs: creating /boot/initramfs-lts for 6.6.71-0-lts
Executing mandoc-apropos-1.14.6-r13.trigger
Executing syslinux-6.04_pre1-r15.trigger
/boot is device /dev/nvme0n1p2
Executing texinfo-7.1-r1.trigger
OK: 5847 MiB in 1489 packages