Ebay, just be sure to list them as American and mention they will not work on a EU console, I'm sure there will be someone who has a US console who will be happy not to have to import themok now the problem is where to sell the ntsc games such as mario kart 7 / new super mario bros 2 / mario open tennis ?
Get your friend to take a photo of his system page. (I know his may be at 4.5 or beyond, but just do it ya ;D )
Also, do the trick I quoted below:
Anyway to be clear, is that error from trying to update?