@ogra: Correct this should be theoretically happen during the boot. As you have mentioned it is done by snapd daemon but after booting it is not started yet. First ramdisk image is loaded and ubuntu-core-rootfs script shall get executed which tried to mount core.snap to /root. Please correct me if I am wrong here.
First of all I am not able to figure it out that why /tmpmnt_writable/system-data/var/lib/snapd/snaps/core_2314.snap file is removed? Next after re-boot when system mount /tmpmnt_writable to writable partition in SD card then why core_2314.snap file is not available in “/tmpmnt_writable/system-data/var/lib/snapd/snaps” as it is available in writable partition.
Still I am not able to figure out why core_2314.snap is not copied to /tmpmnt_writable/system-data/var/lib/snapd/snaps/ on my system. Am I missing any configurations?
I also checked the content of /var/lib/snapd/seed/assertions directory. All files are present *.account-key, *.snap-declarations.
Please find below content of seed.yaml file
- name: core
- name: olimex-a20-olinuxino-lime2
- name: olimex-a20-olinuxino-lime2-linux