According to research done by those looking to help users root and unlock the latest Android handsets, AT&T’s version of the Samsung Galaxy S4 comes with a locked bootloader to prevent users from loading their own custom software.
In a message to Android users at large, Steve Kondik who manages the custom CynagonMod ROM community, concluded that he’d confirmed that the Samsung Galaxy S4 on AT&T authenticates the recovery and boot software loaded on to it before it lets its run on the device.
Why this is being done specifically to the AT&T version of the Samsung Galaxy S4 is unknown though Kondik does seem to believe that it was forced on the device by AT&T because, in his view, “Samsung has always been developer-friendly so I am guessing their hand was forced.”
Kondik goes so far as to declare that he wouldn’t recommending buying the Samsung Galaxy S4 on AT&T and that users who want to run CyanogenMod or any other custom ROM should look elsewhere. It’s unknown if other versions of Samsung’s flagship launching on other carriers in the United States may also have locked bootloaders.
Bootloaders are simply the code that instructs a user’s device to load the operating system that’s been installed on their device. With an unlocked bootloader users can load up their own custom software or software that’s been created by communities like CyanogenMod, for example. Because Android is an open source platform, users can – in theory, install and customize the software to do exactly what it is they want it to do.
In practice Android hardware creators like Samsung, and Motorola sometimes lock the bootloader on their latest devices with little or no indication that they’ve done so until a user attempts to alter their device’s software. Though it is contrary to the open source philosophy of Android, it’s believed that the mobile carriers and hardware creators lock the bootloader on devices as a way to protect the investments they’ve made in testing the device on their network and convincing the customer to buy the device.
It’s also believed that locked bootloaders are put in place to protect users from themselves. An accidental change to a device’s bootloader could render it permanently useless to the user.
Users looking to customize the software running on their device should look at devices who encourage the practice. HTC allows users to purchase an unlocked bootloader version of its latest flagship, the HTC One online, while Google’s Nexus 4 line also does the same with slightly more modest specifications and pricing. Users can also unlock the HTC One bootloader later.