This normally happens on Samsung devices that runs on Android 5.1 Lollipop and above when you install a custom binary. When unlocking a phone to use all network, sometimes we flash some custom binaries on the phone which can trigger this this annoying message “Custom binary blocked by FRP” and also the phone will not boot. The following tutorial below will show you how to fix this problem in just few easy steps.
Download and install Samsung usb drivers from here
Download Miracle box from
Put your Samsung device into download mode by holding the button combination below
Volume down + Home + Power button for about 3 secs
When you see the Triangle, press volume up to enter download mode
Now connect device to PC with USB cord
Launch Miracle Box
Select Samsung tab and click SCAN button
you will see something like COM35(SAMSUNG Mobile USB Modem)
under mode, select Download and click GO button
Now select Reset frp from the menu list below and click Start Button
Wait for the process to complete (takes about 5 secs)
When you see All Done, know that the process is complete
The phone will reboot to normal
When the phone boots up normal,
Go to setting
Enter About and tap Build Number 7 times to enable developers option
Go back to settings and open developers option
Turn on developers option
then scroll down and turn on OEM Unlock
When the pop up “Allow OEM Unlocking” appears, Select TURN ON an input device password
When it’s done reboot the device
Thats all you can now enjoy your device without fear of locking out again
Hope this helps
source romkingz