Help Htc one XL. Boot loop development mode

[Nanosx]

Hi, I'm having a problem with my Australian version Htc one xl on telstra. I was trying to root my device when it got stuck on a boot loop, saying this mode is for development purposes only on the the screen on boot. It would do this for a couple of seconds then re boot. I've tried entering recovery mode through the fast boot menu but just goes back into the boot loop.

Any body now how I could fix this? I don't mind recovering to factory settings if need be. I should also mention complete noob when it comes to this stuff.

Extra info. In the fastboot menu saying Tampered and unlocked. I have also boot loaded my device

Thanks