So to get rid of update nags, boot your 3ds into recovery mode (is that what it is called?) and click cancel. Recovery mode is entered by pressing D-pad Up+l+r+a when you turn on your 3ds. This isn't confirmed to work every time, but that seems to be the case with my 3ds on 10.1 since I have not received any update nags afterwards. I don't think I am the first to discover this, or that this is the correct place to put this xD I don't know where credit is due, however.