Hey, reaching you all to give an update.
Thanks to the inestimable help of @Arvil investigating the dt.img generation (among other things), we have achieved to have a functional recovery.img (and probably a booting boot.img too, we are still testing) and have a working flashable zip.
System is stuck in a bootloop yet but good news are we are making progress and are enthusiastic and motivated, 
I’ve updated the status in the porting wiki accordingly and removed workaround for two errors we don’t have anymore, 