There is a very simple solution for most iGO8 and Primo versions, without the need to complicate the path:
- Delete all rows in [folders] section in your the sys.txt if there is any.
- Create folder Addons (or iGO) on the root of SD-card , and put in it folder Content, like in original main iGO folder. In content is standard structure - buildings, maps, poi... In this case, Primo automatically read additional content from it.