The slot is supported. My SD car would not work at first then it suddenly appeared. It is fat32 16gb card. I did check what was on the card by plugging it into my win7 machine and it threw errors, which I fixed. It started working after this, but not sure if that was relevant. Swapping TOH backs also seems to cause some issues.

One thing that does not work is support through my win PC when the Jolla is connected. I can see the phone but not the sd card