"not if you do it right, i just did it to mine, got the sprint software and did the hard reset to bootloader mode before doing the screen alignment, if you do that sprints settings iinstall and delete your old ones (you can write them down dial ##778 and click view and record all the info), but anyway i then installed the Telus modified version by dcd (i tried keys ROM from xda-developers forums.. but didnt fly) and it booted up ickity split no shit, with WM 6.1 (threaded texts, bit snappier, task manager), and GPS chip works awesome. Installed GPS speed sentry and it tells me when Im speeding better than my own speedometer"