Flashing logo loop

Two days ago this started. My iPhone 5 would not turn on no matter it's full charge, it would only show signs of life when plugged into the wall but all it did was flash the apple logo on and off in a continuous loop. I googled this and everything I read suggested putting it in recovery mode and then restoring it or updating it. I did this on my of but every time I attempted it, itunes came up with error code 21. I googled that and did everything it suggested (updating iTunes etc). Still no luck and same error code. I then attempted to try on my desktop Mac but the same thing happened but with error code 2001. It just suggested that my cord was faulty which is definetely not true considering is only a few weeks old and works fine for every operation. I have been without my phone for two days and can't book an appointment at my local Genius Bar for 2 weeks. Please help!