Just one year ago I bought 2 Express II's.
6 months ago the first one indicated that it didn't have enough power. I pulled the USB cable from the supplied wall adapter and put it in the TV USB port. All is well.
The second one failed last night. Again, I pull the cord from the adapter and plug it into the TV USB port. All is well.
I thought that they had only a 90 day warranty. I see now that I was wrong.
Since the phone number for Support just hangs up, I would like to know how Roku will fix this warranty issue.