For what can the SD card be used with the Spitz AX-3000?

Can I increase the internal memory?
Can I install more packages?
What format I have to use ext4, FAT, exFAT?

If I have one already installed, how can I format it?

Thanks

Can you see the device node of the SD card on the X3000?

If it generated a device node: /dev/sda,you can exec the followint:

fsck.ext4 /dev/sda