Don't use OpenATV 7.6.1 at the moment better way update your actual image from today is available blu button to add more slots on SD or USB device.
You can find plugin attached to install on other images different than OpenATV which don't have plugin inside and you can add more slots (6 are by default on DM 9xx) by SD micro and USB above 8/16/32/64 Gb, I used 32Gb for 9 extra slots.
For DreamOS images you must convert from .xz to .zip file and option is available with BackUpFlash plugin by (RAED & mfaraj57)
All new images must be installed from OpenATV menu " Flash on line "
Make a full backup before starting I'm not responsible for any problem you may get during process.
