Well coleague, it is very often discussed
In sys.txt you have two lines under [folders] section
.....
;has_secondary_root=1
;android_secondary_root_path="/storage/MicroSD/addons"
(full section is
data_folder_name="iGO_World"
linked_root_list="/storage/emulated/0....
.... but it does not metter, only those two lines)
Remove ; in front of both lines, change MicroSD according to name how your system "see" mSD card. Proper name can give you X-Plore, TTC, or similar file manager.
At your card make folder addons in root, with folder content in it.
In folder content should be other folders: building, DEM, map, phoeneme, poi. Like original structure in iGO/content. Then put all needed files in proper places.
Spoiler: pic
I'm not sure for your full path, end of line in sys should be according to Zephira's post (his error)
"/mnt/m_external_sd/addons"
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