Making FFU firmwares for Lumia devices

You’ve probably been aware since a few months that I’m able to make FFU firmwares for Lumia devices that are flashable on retail unlocked devices without any issue. Some of you may have also noticed a tool I open sourced on github that enables you to exactly do this. However this tool was never meant for wide use since it’s not finished and requires special instructions to be used properly and safely for a device. This post is aimed to explain you how to use this tool.