[steps]

I know Sprint SAYS it has to have the original OS, but I have sent my phone in to be replaces many times with a custom OS and NEVER had any issues. Just tell them your phone was having issues with the USB port and you THOUGHT upgrading to the new OS would work but NOW you see it is a hardware problem and not software...OOPS! Please stop stressing out over this...but since you have the OEM OS flashed, you're all good!

Next time, just take it to a Sprint AUTHORIZED REPAIR CENTER...they are much easier and FASTER to deal with then a Sprint Corp store and won't give you headaches.