Install Custom ROM Samsung S4 SGH-i377 I'm going to make this short and sweet:

I have a Galaxy S4 AT&amp;T on 5.0.1 variant that I want to install Resurrection Remix on. I cannot find any way to do this. This phone has a locked bootloader.

How can I unlock the bootloader, and install a custom recovery as to flash the ROM? [Possible to downgrade to 4.4.2 and then install it??]
First thing to know when you purchase an Android device from AT&amp;T or Verizon: bootloader is locked and not unlockable. Downgrade is also a no-go for Samsung devices.

XDA-Developers is the place to go to if you want any sort of development. There is a way around the locked bootloader (namely, Loki/Safestrap), but it's nowhere as elegant, and since I don't have the phone myself, I don't know whether it applies to your current Android version. Do read carefully and good luck tinkering with your phone.