Weird. I've upgraded both iPhone and iPad without problems. At first it took a bit longer to find the 4G connection and seemed more fluctuating, but after a minute or so it worked apparently fine. I haven't phoned anyone yet.
Having the computer checked at Apple's won't cost you a dime. My guess is the the GPU is screwing around, were this the case, I'd probably get a new one.
A couple of questions from a DIY wannabe. Is this easy enough to build as a first project for someone who barely can solder? Will it decently drive the 007 (I mean 717 level of driving) at 350V in the PS?
I've read that Kevin recommends the 400V configuration, but Birgir tried 350V and I'm not sure about the results. 400V trafos are a bit more expensive.