The 357MB update may hold a locked bootloader as a requirement for Samsung Knox support -- hackers beware
The Samsung Galaxy S4 on the Sprint network is seeing a general rollout of the MF9 update, and it has a few welcome changes baked in. Users who have already received the update have noticed the following changes:
Status bar transparency now works with custom wallpapers
The addition of a briefing app, and an SPDclient app
A potentially locked bootloader
The first and last items on the list will get the most attention from the community, we're sure. As of now, nobody is certain that the bootloader is locked, but speculations are running high and the bootloader was updated along with the modem and kernel. A locked bootloader could very well be a requirement for Knox support.
If you're rooted or have a custom recovery installed, you won't be able to install this OTA. You'll need to revert back to factory settings or wait it out for the custom version from your favorite developer. If you're into the whole root and ROM thing with your Sprint S4, you might even want to wait until the bootloader's lock status is confirmed.
For everyone else, the OTA will come the normal way, and you'll be faced with a 357MB download to install. For more information and discussion, see the links below.