It's quite easy to debrand the HTC One (and also do it in a way you are still elligable for warranty) with revone. You can do this by changing your CID (carrier ID) and then running an "401" ruu. With revone you can s-off your phone so you get complete control. With revone you can also unlock and lock your bootloader without HTC-dev, so your phone will always be elligable for warranty, even if you root (because you can remove all traces of rooting!)
Follow the following guide to get s-off:
http://forum.xda-developers.com/showthread.php?t=2314582 Once you are s-off, get fastboot:
http://forum.xda-developers.com/showthread.php?p=42407269 and boot into fastboot mode (power + vol down; and connect to usb), start fastboot (i haven't tried this installer but i think there will be a start menu entry which opens a command prompt in the right path) and do:
fastboot oem readcid take note of the output, copy/paste it somewhere for future reference, should you want return to stock vodafone
fastboot oem writecid HTC__001 for international unbranded
or
fastboot oem writecid HTC__E11 for dutch unbranded (take note the CIDs need to be exactly as I have written them, with capitals and double underscore __)
check your cid again:
fastboot oem readcid You can flash a "401" RUU, be warned though that running an RUU will bring your device to a complete factory state, so EVERTHING will be wiped. Backup before running an RUU:
http://bugsylawson.com/files/file/1822-ruu-m7-ul-jb-50-htc-europe-1284017-radio-4a13323127-103111310... Now enjoy your unbranded phone and speedy updates from HTC instead of vodafone. Should you ever need to return your phone for warranty this can all be completely undone without any traces left