|An 8gb drive would not have a FAT partition if it fills the drive - that has a limit of 2.1gb max - it would be a FAT32 partition.|
You could have a FAT partition on it of 2.1gb or less, and the rest of the space on it could be un-allocated - "raw".
Should you have stated 829mb, not 829gb ?
If you're truly seeing two drive letters that have the icons for a removable drive, and you have no other removable drive or memory card plugged in, you probably need to use a program to fix data damage on the pen drive.
Troubleshooting USB device problems including for flash drives, external drives, memory cards.
See Response 1: