http://www.hynix.com/inc/pdfDownload...dram/down/NAND Flash.pdf
You have 2GB.
I *strongly* recommend that you extract the firmware with s1res and keep it for backup.
It seems that your version of MP3 Player Utility may not detect the disk size correctly for the newer players. Try using version 10.00.
Also, after reformatting you should physically disconnect the device from the computer and replug it into preferably another USB port, to allow proper redetection of the partition sizes.