booster: `booster: mount(efivarfs): no such device` when UEFI booting on Alpine Linux via QEMU

@anatol I am excited to have come across Booster, and pretty keen to use it for generating my initramfs; thanks for creating it! I hope it gains wide adoption in the various Linux distros.

I initially tried getting it working on Arch Linux with a ZFS root file system. After beating my head against the wall for a few days I found #33, and realised it was never going to work 😄. So I switched over to XFS and was able to get the system to boot.

I’m now trying to reproduce this in Alpine Linux. I’ve spent a fair amount of time over the last several days trying to get it working, but just can’t seem to get it to work no matter what I do–even though it seems others have?

If it helps I created a repo containing a (simplified) Packer template to build the QEMU images I’m using for testing with: https://github.com/111A5AB1/packer-alpine-booster

It builds from Alpine Linux v3.15.4 “Extended” and “Virt” ISOs using edge repos; and installs the Booster package from Testing. Two additional Grub entries are also added to boot from Booster for the standard (lts/virt) and “edge” kernels.

Summary:

• Alpine Linux mkinitfs made initramfs boots fine (first two Grub entries).
• Booster made initramfs with lts (extended)/virt (virt) kernels just hang after “Loading ramdisk …” (no output even with Booster debug enabled)
  • Extended: 5.15.37-0-lts
  • Virt: 5.15.37-0-virt
• Booster made initramfs with edge kernel appears to try and start booting, but fails very quickly with booster: mount(efivarfs): no such device.
  • Edge: 5.17.5.-0-edge (x86_64)

In addition to the setup in the repo I’ve also tried combinations of making a Universal initramfs, adding modules and additional files, as well as using Booster built direct from main (master). I originally* tried to boot directly via EFI without a boot loader; I saw the same results of the “Booting intramfs” hang and “efivars” issue. I made one of the initramfs images with busybox+ls and confirmed an ls /sys/firmware/efi/efivars is empty–it seems Booster is maybe not mounting it for some reason 😞?

*Booting directly from EFI is my desired end goal; I dropped back to GRUB for testing since its the default/traditional Alpine installation via setup-alpine.

Thanks very much in advance for pointing me in the right direction of how to get Alpine booting with Booster created initramfs images. Let me know if you need any more information or if there is anything you want me to try.

Cheers!