Comment 1 for bug 1871424

do_install() here is to *upgrade* the installed package to the jump-off version in the OEM archive. Note this code is only run if the target_sources_list exists - which means that the oem metapackage *is* already installed (happens via scripts/simple-plugins). So that means two things:

  - the installer can get the right kernel installed (since it is shipped in the pool)
  - when we boot into the installed system and it eventually gets online, we will already know at this point that there's an OEM package and can try to do the update/upgrade dance there

The second point implies that the fix for this issue is somewhere else other than ubiquity. I'll add a task for update-manager for now.

This work definitely needs doing; we will schedule it after the 20.04 release.