Long story short, I had an iPhone 5 which had swollen battery. Apple Store gave me a refurb to replace it. This was in late October 2014. For the past few months now, my phone randomly reboots to the black screen with the apple logo. I've restored it several times to no avail. It's up to date with the latest ios. Any ideas what might be doing this? It's hard for me to get over to the apple store so I'm going to try to go as soon as I can. Thank you.