[Bug 1850678] Re: flash-kernel only updates the dtb of the Pi it's on

[Łukasz Zemczak]

** Description changed:

+ [Impact]
+ 
  Specific to the Raspberry Pi, when flash-kernel is executed to copy
  things to the boot partition, only the dtb of the Pi that it is being
  executed on is copied. In order to support moving the SD card between Pi
  models, flash-kernel needs to copy *all* dtbs provided by the kernel to
  the boot partition.
  
  Consider the case of SRUing Pi 4 support to Bionic. Bionic does not
  currently support the Pi 4, so a user must necessarily boot their Bionic
  image on, say, a Pi 3. If they then upgrade to a kernel supporting the
  Pi 4, flash-kernel will only copy the dtb for the Pi 3 to the boot
  partition. If the card is then moved to a Pi 4 it will fail to boot due
  to a missing device-tree.
+ 
+ This would be a very welcome bugfix/feature for eoan as well, since
+ that's where we had first, proper pi4 support.
+ 
+ [Test Case]
+ 
+ TODO
+ 
+ [Regression Potential]
+ 
+ The fix comes with a fair amount of flash-kernel code cleanup. On one
+ side, more changes might feel more regression prone, but on the other -
+ since we are doing a direct backport from focal, this means that there's
+ no chance of us forgetting a change and making the backport incomplete.
+ 
+ There is risk involved, as this SRU changes how basically flash-kernel
+ performs updates for all the pi variants. The test suite however has
+ been extended, so to reduce regression potential. Potential regressions
+ should be looked for in missing DTBs during flash-kernel updates and
+ broken boot (due to the modifications made to the boot script). That
+ being said, most of those issues should be instantly visible during
+ verification.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to flash-kernel in Ubuntu.
https://bugs.launchpad.net/bugs/1850678

Title:
  flash-kernel only updates the dtb of the Pi it's on

Status in flash-kernel package in Ubuntu:
  Fix Released
Status in flash-kernel source package in Bionic:
  New
Status in flash-kernel source package in Eoan:
  New

Bug description:
  [Impact]

  Specific to the Raspberry Pi, when flash-kernel is executed to copy
  things to the boot partition, only the dtb of the Pi that it is being
  executed on is copied. In order to support moving the SD card between
  Pi models, flash-kernel needs to copy *all* dtbs provided by the
  kernel to the boot partition.

  Consider the case of SRUing Pi 4 support to Bionic. Bionic does not
  currently support the Pi 4, so a user must necessarily boot their
  Bionic image on, say, a Pi 3. If they then upgrade to a kernel
  supporting the Pi 4, flash-kernel will only copy the dtb for the Pi 3
  to the boot partition. If the card is then moved to a Pi 4 it will
  fail to boot due to a missing device-tree.

  This would be a very welcome bugfix/feature for eoan as well, since
  that's where we had first, proper pi4 support.

  [Test Case]

  TODO

  [Regression Potential]

  The fix comes with a fair amount of flash-kernel code cleanup. On one
  side, more changes might feel more regression prone, but on the other
  - since we are doing a direct backport from focal, this means that
  there's no chance of us forgetting a change and making the backport
  incomplete.

  There is risk involved, as this SRU changes how basically flash-kernel
  performs updates for all the pi variants. The test suite however has
  been extended, so to reduce regression potential. Potential
  regressions should be looked for in missing DTBs during flash-kernel
  updates and broken boot (due to the modifications made to the boot
  script). That being said, most of those issues should be instantly
  visible during verification.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/flash-kernel/+bug/1850678/+subscriptions