My Wiimote stopped working. How to return to the Wii U mode from vWii

Even though they are "duplicate" Miis as far as you are concerned, they are 2 separate Miis as far as the system is concerned.

If you deleted the Mii that was imported from the 3DS, then any content tied to that Mii would be gone. Consequently if you deleted the Mii that was imported from the Wii, then any content tied to that Mii would be gone. Ergo, if you deleted the Mii that was imported from the Wii, then that would cause your Super Mario Galaxy 2 to revert as well as any Wii-specific data.

I tried this by "duplicating" a Mii using my 3DS, original Wii, and Wii U.

Okay this CAN work however it does require the TV; you can't do this gamepad only (with or without sensor bar; the menu appears on the TV only). when the "point the wiimote at the TV" screen, plug in your Wii Classic Controller and move the left joystick; a hand cursor should appear. Highlight "gamepad and TV" or "TV only" as you please, then press A on the classic controller. It should boot right to Wii mode without the sensor bar now.

Also...the gamepad has a sensor bar in it! It actually works better than you'd think, though it's definitely best with a gamepad stand. You can't use the gamepad sensorbar to get into Wii mode unfortunately, so you WILL need either a classic controller or a sensorbar to get into wii mode, but after that you can use the gamepad as a sensor bar if you so wish.