[popcornmix]

The PSU is 2A so no problem there. I'm not sure how much power the tuner requires but it works fine on my B, so unless the v2 defaults to supplying less power to the USB ports than the B I guess it's probably not power related. Guess it won't hurt to try adding that line and see if it makes a difference though.

Adding "max_usb_current=1" is pretty harmless. Worst case is the USB port will swallow more current than the PSU supplies, and the voltage drop will crash the Pi, but from what you've said that seems unlikely to occur. Give it a try and see if it helps.