Unlock Samsung S5(SM-G900W8) bootloader without rooting
Unlike HTC, 1) most older non-AT&amp;T/Verizon Samsung devices have their BL unlocked by default, and 2) Odin to Samsung is fastboot to others, just you can only access it with Odin/Heimdall on PC.

Just find suitable images (e.g. TWRP) and flash away with Odin.