Instructions
Turn on your Xbox 360 and sign in to your gamer profile. Ensure that the Internet is functioning and connected to the console.
Connect to Xbox LIVE; when prompted to update, select "Yes, update now." When you are returned to the dashboard, your update is complete.
Insert the USB flash drive into one of the USB ports on the Xbox 360.
Go to "My Xbox" from the dashboard menu. Use the thumb sticks to navigate and "A" to accept selections. Select "System Settings" and then "Memory." Under "Memory," go to the "Storage Devices" screen and select the "USB Storage Device." Press "A."
Select "Configure now" to configure the flash drive to function as an Xbox 360 storage device. Select "Yes" when prompted to continue formatting. Once the formatting is complete, use the USB flash drive as a memory card.