Whoever has recently jailbreak their iOS 10.3.x iPhone 6 series can you try to install House Arrest Fix or Apple File Conduit 2 to see if you can get root access via USB with programs like iFunbox. This install in my opinion should be done by people who saved their SHSH blobs just in case. I was unfortunate to not get the chance to save my SHSH blobs in time before 10.3.1 was unsigned. I tried installing Apple File Conduit 2 and my phone crashed and a lot my app icons were missing but luckily my g0blin jailbreak app was still there and I was able to re-jailbreak my phone to bring up my app icons back up.