Question [Q] Downgrade bootloader is

I've found this about downgrade bootloader:

My question is:
Is anybody who knows how to modify older bootloader to bypass verification during uploading by ODIN?
Samsung S4 GT-9506 (most unsupported device) - Otherwise I don't understand why Android/iOS/WP are so popular they are totally useless without root. They haven't got basic things like old good Symbian on my Nokia E52!