1. Firmware and custom ROM difference. For example I have android LP but to upgrade to MM custom ROM I need to update my firmware which goes with bootloader and some other stuff for MM. Why is that and what's the difference?
2. When flashing a new ROM, if I wipe (TWRP) dalvik, system, cache, data and internal storage and ROM fails to install, everything is deleted including bootloader. Now it's obvious to me why but where is it stored exactly and what's the android OS storage hierarchy like?
3. Why can't I downgrade from let's say MM to LP directly by just deleting the MM and installing LP?
4. How can I avoid hard bricks because everytime I tried to flash a ROM on my zenfone 2 z00a I managed to hard brick it every time before finally installing it by following some step by step tutorial (I really want to know how to actually do it on my own), and it's a long process of unbricking
5. Are there any good sites that explain android system apart from reading the documentation on official site