LOL its been that from day 1

Still considering if/how this should/could be implemented in recovery.
What we do need (thank stskeeps) is img2simg tool in order to split up the raw image file in multiple image files of 500M size (due to memory.
I have build this tool for armv7hl so that it may be used on-device
(https://build.merproject.org/project...me:nielnielsen)

stskeeps have also confirmed that the correct name of partition 28 is sailfish as I found out by parted in a previous post in this thread.

Given this information, it actually should be rather trivial to finish this and create a script that could be run, even on device, allowing users to create that rescue image.