Finally I have managed to make it so that one can make a SailPi image from a .ks (kickstart) file and use it to create a custom image by themselves. The process is quite straightforward for those who have a SailfishOS SDK or familiarity with Mer Platform SDK. Either SDK will have the necessary tools to complete this guide.
Start with downloading the .ks file from this link. Please do note that its a raw text link to a gist, so I suggest you do a curl -L -O to that inside the SailfishOS SDK command line.
curl -L -O https://gist.githubusercontent.com/locusf/7fbc28ec37013a900c80/raw/d466fff484124ac5f9a5f268cb924f0b7aafbfd4/sfos-rpi.ks
Then issue the following command, be sure to be inside the shared directory as if you issue this command inside the SailfishOS SDK default home directory, you will very quickly run out of disk space!
sudo mic cr raw –debug –arch armv7hl -o sfos-rpi2-18.104.22.168 –record-pkgs=name,url,license sfos-rpi.ks
This will result your actual image to reside in this directory “sfos-rpi2-22.214.171.124”, with filename “sfos-rpi-sda.raw”. Then as normally with any Raspberry Pi image, choose a disk image writing software to write it to a MicroSD card. Insert to Raspberry Pi 2 and you should boot to first run setup of SailfishOS!
Thanks for reading and have fun!
locusf (Aleksi Suomalainen)