According to http://mobilesyrup.com/2013/05/01/samsung-galaxy-s4-review-video/
(Sorry if I messed up the tags for the quote, lol)
- It appears that Samsung has left the device?s bootloader alone on the Canadian builds which, unlike on the AT&T model, means there shouldn?t be an issue loading new software on it. The problem is that because the Canadian model shares the same underlying architecture as the aforementioned U.S. variant, initial availability of custom ROMs and kernels will be limited due to a shortage of developers with access to the phone?s bootloader. This is an unfortunate situation alleviated somewhat by the fact that the device runs Android 4.2.2, the latest version of the Android software.
(Sorry if I messed up the tags for the quote, lol)