Make sure you have a Samsung Galaxy S5 (this is mainly for the 900F), use Odin to flash the Modem and bootloader from xXx.
To use Odin read the top bit by edgarf28
But most inportant follow what ::indie:: has posted in the op, where is says ...
Hello Omega friends,
I am back in business, Omega v18 is almost ready based on the latest firmware.
Please pray for my family, we are having difficult times here at Greece :(
Is great to hear you again. Hope all of you and famil...