You will be able to update the firmware without formatting the device.
When updating the drive's firmware, do not select to format the device if prompted by your PC as this will delete your data. Buffaloīe sure to keep your drive up to date with the latest firmware ( ). These device(s) have been subjected to basic performance tests, and we will expand the list below as more devices are confirmed to work with Wii U. Firewire, similar to the USB in its plug and play operation, but is available in two speeds: Firewire 400 (which matches the. USB, the predominantly used connection variant, simply plug in and your computer should detect it automatically. We have found that the following external storage devices work with the Wii U system. There are two main ways to connect an external hard drive to your machine USB and FireWire. Please visit the websites listed below for information on each manufacture's latest models. Nintendo cannot guarantee the availability of all models. Due to the wide range of external storage devices, usability and performance will vary. To ensure maximum performance between your Wii U and an external storage device, we recommend using a hard-disc drive (HDD) with a dedicated power source (i.e., using an A/C adapter). Our complete FAQ on using external storage with the Wii U may also be helpful.Please contact the manufacturer of the USB hard disc drive if there are technical issues or problems with your USB hard disc drive.Specifications of these devices are subject to change, and there is a possibility that these devices may not function properly with the Wii U system due to a specification change.We do not guarantee the performance of the devices listed below.Once a device has been configured for use with a Wii U console, it cannot be used with another Wii U console, PC, or MAC unless it is reformatted.Please be sure to back up any content before formatting the external storage for Wii U as this content cannot be recovered.To optimize performance and ensure a consistent experience, all USB storage devices must be formatted and configured for use with the Wii U console. If you ever decide you want to come back to the Wii-U, you can re-download, then copy from the PC/MAC to whatever hard drive you end up purchasing in the future for NX / other gaming hardware.