I didn't have any problem with wifi with the HTC MHL adapter attached. What I did have problem with was getting the picture and sound to show up on the TV. After reading reviews for the adapter on Amazon I found one where they had to restart the View with the adapter connected to get it to work. Did that and it worked for me, and wifi still worked as well.
Kyo 6035 > Kyo 7135 > Palm 800W > HTC EVO and HTC EVO View