Toshiba pendrive shows 4 MB instead of 8 GB; what could have happened to it? [duplicate]

I have a Toshiba 8 GB pendrive. All of a sudden, it's showing total space 4 MB. I have tried diskpart and various other software, but no gain. The disk management is also not showing unallocated space. Can someone suggest what happened to the pendrive?

The internal flash mapping table got corrupted. Due to the use of extremely cheap component, it sadly sometime happens to pendrive.

If the manufacturer (or someone else, as the controller manufacturer) publicly released the tool yo reset the flash table, you can try to use it to recover all your space. Anyway, I will not trust that pen drive anymore.