My 64Gb card is formatted ext4, and I need to mount it manually every time I reboot (root, "mount /dev/mmcblk1p1 /run/user/100000/media/sdcard"). But that alone isn't enough to see the folders. I made a bunch of symlinks so that I have /home/nemo/SDcard, /home/nemo/Music/SDmusic, /home/nemo/video/SDvideo etc. This probably isn't the best way of doing this, but it works. Although after mounting the SD card after reboot, you might need to tell tracker to reindex. There is "tracker-sd-indexing.sh", that seems to enable removable media indexing and restart tracker.