replace in fallout4.ini
sResourceDataDirsFinal=STRINGS\
with
sResourceDataDirsFinal=STRINGS\, TEXTURES\
Put the "sky" folder on Fallout4\Data\textures
create "textures" if you don't have.
To unistall, remove the "sky" folder.
Based on
http://www.nexusmods.com/fallout4/mods/737/?