I am performing some tests on android devices, to properly do this I need to first unlock the device bootloader and run my tests on the device after which I then root the device and perform the tests again. I was able to unlock the bootloader for an HTC One m8 device using the offficial HTCDev instructions and then rooting by using TWRP Recovery and SuperSU. I need to replicate this process step by step for a Samsung Galaxy S5(SM-G900W8) device but I can't figure out how to unlock the bootloader for the device without rooting first. I have tried to follow the instructions here but it gets stuck in odin mode(step 7) and I have to do a battery pull. My question is how does one unlock the bootloader for this device nd then go about rooting it? Thank you.