How to Add External Storage to Fire TV Cube
The Amazon Fire TV Cube comes with 16GB of internal storage, and while that's double what the Fire TV and Fire TV Stick pack, you may run out of space eventually. Fortunately, the Cube can support up to 128GB of flash storage, which you can add via a memory card or a USB thumb drive.
Unfortunately, though, you'll need an additional device, called a USB OTG (on the go) cable. I used the Iogear GoFor2+ USB OTG, which costs $11.96 on Amazon. Also, you'll need to format (i.e. erase) your memory to use it.
1. Plug your storage into the OTG cable.
2. Plug your OTG cable directly into the Fire TV Cube's MicroUSB port. I say directly because it didn't work when daisy-chained into the Fire TV Cube's Ethernet adapter.
3. Select Settings from the Home screen.
4. Select Notifications.
5. Select Limited Device Access.
6. Select Yes.
7. Select Yes.
You've added your drive, and you can view storage capacity under Settings/Device/About/Storage.