Here I m giving you the guide to enable online theme.
First root your Primo S2 Using this Tutoril- Primo S2 Rooting Tutoril
Then follow the instructions below:
1. download build.prop editor from play store.
2. open build.prop editor and grant superuser.
3. search "theme" on build.prop editor
4. change the value of :
" ro.gn.theme.net.support" no to yes.and save.
" ro.gn.theme.style " 0 to 1 and save.
5. Now search "change" on build.prop editor and change the value of :
"ro.gn.change.support " no to yes.
Now reboot your device and check in theme section have download option. but its painfully slow speed to download though.
Join here for instant dev support for Primo S2: www.facebook.com/groups/waltonprimos
Our Project: http://github.com/waltonproject
Please click "Thank" button if this helps you