Chris Vogel's avatar
Chris Vogel
@me@chrichri.ween.de

: @okias@floss.social is doing a lot work to mainstream patches to the kernel. During a meeting of Phosh.mobi e.V. members I learned that there seem to be not many testers for . I still had a broken Axolotl sitting on my desk…

  • repaired the phone that originally had been bought as part of a deal
    • cleaning inside (residue from water contact)
    • new display (two lines of broken pixels)
    • new usb-c pcb (didn't charge, data broke during testing)
  • learned about edl to recover if phone wouldn't boot to fastboot anymore (yes, really had that situation later 😉)
  • learned about the difference of fastboot and fastbootd mode
  • learned about u-boot and the boot chain on the phone
  • learned about dynamic partitions used in Android and how to use them from
  • learned about pmbootstrap
    • to build my own device images (mixture of existing axolotl and sdm845 to be compatible to the phone and the usage with u-boot and dynamic partitions)
    • changed pmbootstrap to build small (92M) boot image for boot_a/b partition
  • tried to get more space for out of the phone for boot & root than provided by boot_a/b and system_a/b
    • resized userdata of Android
    • created two additional partitions for postmarketOS
  • learned how to recover from kernel not booting without re-flashing
    • u-boot usb mass storage mode exports the mass storage of the phone over usb-c
    • phone connected to an aarch64 system ( running )
    • mounting encrypted partition, boot and what-else is needed
    • installing kernel packages via apk while in chroot on Librem5
  • learned how to compile a kernel using ./envkernel.sh and pmbootstrap

Now I'm quite sure I can recover from any failure I will encounter while testing sdm845 kernels and I have the following setup on my Shift6mq:

  • ShiftOS-L with small userdata partition in slot_b
    • applications for demoing the phone installed
    • work profile to contain closed source applications
  • postmarketOS edge installed on partitions behind userdata
    • u-boot on rescue_a
    • 1GB pmOS_boot
    • 60GB pmOS_root
    • applications for demoing
    • multi-user: my testing user, demo user
    • everything except cameras work
  • dual-boot possible on-the-go: enter fastboot (by holding vol-up at start), change slot, reboot

I put my notes on the postmarketOS wiki.

I started two merge requests:

I'll carry the phone at - Chemnitzer Linux Tage 2026 - on saturday 28th this month. I'll mostly be around the "Linux on Mobile" booth.