MicroSD card must be class 10, up to 128 GB and formatted to FAT 32.
If you want to back up your files, you can insert a microSD card in the slot intended for this purpose. The slot is located in Ulo’s back (see quick start guide point 7.):
Make sure you inserted the microSD card angled side first and label side down.
The microSD card shall be sloped.
Don’t force, it won’t lock into the slot.