On my Galaxy Grand Prime SM-G531F, I am in stuck a boot loop with "Custom binary blocked by FRP" after my first attempt (ever) at a custom ROM. I *did* get the ROM installed and running, but then I messed with Xposed (?) and installed it when I should not have. That is what has put me in this loop.
HOWEVER, these instructions are not solving the problem for me! Although Odin does flash and gives me a green "Pass" sign, the phone stays in the loop when it reboots. Where do I go from here?
Note that it won't allow me to boot into recovery, either... only download. I did try to flash TWRP again, but that gets refused because of the FRP.
Many thanks in advance...
A couple of hours later, I figured this out... Maybe the reason can be useful to others.
In fact, the original stock ROM that I had downloaded from "sammobile" turned out to have a problem. I suddenly realized that, as it flashed, it zipped through really fast. I downloaded the stock ROM again, and this time it took a few minutes to flash... as I would have expected. When it was done, it booted! So, I'm back in business to go do it again.
So, if you are having similar issues, check your stock ROM download.