If you bought/plan on buying AT&T's variant of the Galaxy S4, we have some bad news for those of you who like to flash custom ROMs, kernels, and the like: it's locked down tight.
Historically, Samsung devices – up to and including the SIII – have been bootloader-unlocked on AT&T. The Galaxy S4 brings a major change in that respect, as Steve Kondik (Cyanogen) has confirmed that it is indeed locked, in that it "authenticates the recovery and boot images before executing them." In layman's terms, that essentially means that it won't allow any sort of custom recovery or boot image to be flashed and/or run. Ouch.
Steve goes on to say that he "would not recommend buying this device on AT&T if you want to run CyanogenMod or another custom ROM, or if you are a developer and need to work or debug the lower layers." We know that a lot of you are big fans of CM, so this is a pretty substantial statement coming from Cyanogen himself.
Yep, it's confirmed. The AT&T S4 authenticates the recovery and boot images before executing them.
I can't see what AT&T has to possibly gain from this. GSM and LTE aren't magical, tethering is controllable on the server side, and theft-of-services is not possible from the application processor side (or even from the modem side as far as I know). The same device is available on every carrier, so it's not an exclusivity issue either. The modem processor has always been locked, and the casual user doesn't want to mess with that part anyway. Samsung has always been developer-friendly, so I am guessing their hand was forced.
The only outcome I see here is stacks of bricked devices being sent back for warranty replacement due to the ease of causing a permanent boot failure, especially since the device is trivially rootable.
The arms race continues. News flash: MILLIONS of people run custom firmware (and I have the STATS to prove it). This is just a stupid move that will cost you customers and money.
I would not recommend buying this device on AT&T if you want to run CyanogenMod or another custom ROM, or if you are a developer and need to work with or debug the lower layers.
While we can't say for sure, it's probably a safe bet that Verizon's variant of the device will be the same way. Unlike AT&T, Verizon has a reputation of locking down all devices, which includes its versions of the Galaxy S III and Note II. No reason to think that the GS4 will be any different.
Unfortunately, it looks like this may become the new norm for carrier-branded devices in the US.
[Steve Kondik (Google+)]