iPhone 6 Boot loop and Error 9 I have a problem with my iPhone 6. My iPhone 6 bootloops similar to this question: Why would my iPhone 6 be stuck in a dead battery loop?

However, the answers there do not help. In addition, when I try to restore my iPhone, I get an Error 9. I have not tried a new USB cable, but I want to check if that is it before I buy a new one.

I have tightened the battery and Lightning port connections, and this phone was never dropped in water.
iFixit has a solution to your problem.  


  The iPad in my experience is very picky about what cables it will restore with. Error 9 is almost always related to the cable, NOT the dock connector/flex cable. Use the official Apple cable if you still have it, or borrow one from a friend.
  


tl;dr: It's the cable's fault, plug your iPhone into iTunes and update your software again with a different cable.

This has happened to me before. Trying to update software on an old iPod Touch by connecting it to iTunes with a non-MFi cable, got an error message and a crash. Replacing the cable with a genuine Apple one fixed my issue.

If you're looking for a cheap, MFi-certified cable, try this $6 one from Anker. Or get the official $19 one.