So I had my Verizon iPhone 4 flashed to cricket in March on 6.1.2 using evasi0n (it's untethered flash). I have mms, internet, text, and call so everythings good so far. Sick of using cydia ios 7 skins and I want update my phone to ios 7. I haven't done a restore / removed the jailbreak since the flash.

If I was to update to ios7 would I lose my flash & jailbreak? Or should I be ok? Is there a way to backup my current flash so I can restore it in case it goes wrong? Not really looking to go back to the guy who flashed my phone as he kind of fucked it up (headphone jack was working before flash and jailbreak and stops working right after and he claims he didn't do anything).