I have a Cybertech with skill 400. He can RE engineer rank 25 armorings and rank 26 armorings. But he has the "No research" possible probability of getting the recipe. These are armorings which are not slot specific and were dropped by ops bosses. Are there some preliminary recipes that must be learned first before I can successfully learn recipes by RE'ing rank 25+ items?
Can't learn 25s at all.
For the 26s make sure they are drops and not crafted by someone else. If they are crafted by someone else then you can not learn it. You don't need to do anything else prior to learning them.