It's a partition table. More advanced than the old mbr that windows used. Any partition utility will have option to format NTFS with GPT table
I installed the new 1.4.4 firmware and it solves the format problem, But there no option to format as internal storage. This is strange since other Android boxes all have this.
It is there on mine and works without problems even for USB-drives (provided there is no partition on it). Did not try a HDD or SSD.