In order to complete a system transfer, the following items are needed:
Both the source and target Wii U consoles. Each will need to be present, set up, and fully updated, and each will need a working Wii U GamePad paired to the console.
An SD Card with enough room to hold all system and save data from the source Wii U. Software data will be redownloaded once the transfer is complete, so the SD Card only needs to be large enough for system and save data.
A television for the initial setup of each Wii U; however, it is not needed to complete the transfer process. All prompts for the transfer process are on the Wii U GamePad.
A network connection that allows both Wii U consoles to be connected simultaneously.
If Wii Menu content exists on either console, a Wii Remote or Wii Remote Plus is required.
If transferring from a Wii U Deluxe Set (32 GB) to a Wii U Basic Set (8 GB), a USB storage device may be required if you have more data on the Wii U Deluxe Set than the Wii U Basic Set can save to its internal memory.