*initial 2 steps shown to me here http://forum.eeeuser.com/viewtopic.php?id=5548 by HaaTa
Press “Ctrl+Alt+T” to get to the command line then type:
to ensure you have admin privileges
/dev/sdb should be your SD card. To be sure in console type:
which will show you a menu to verify which device is mounted where… We'll continue with /dev/sdb as your MMC/SD card reader Type:
This will bring up the 'cfdisk' console, where you can use arrows to move back and forth between the options listed at the bottom. For a clean format it FAT32 mode:
Use the up and down arrows to switch to any of the paritions shown and use the side arrow keys to select delete, confirm. Wait for the utility to finish the operation, and then repeat for any other defined parition.
Now you should be on the only partition showing (FS type: free space)
Wait 10 sec for it to finish, and then quit.
Congratulations, you're done! Reboot and everything should show up properly.