[Moto E4 Questions & Answers] wajjaw:
I've flashed lineage to an old phone, this is my new phone, so I am familiar with the process in a general way, however I didn't have a backup of stock on my old phone. So that became a problem when I needed to update. And in this case because the ROMs are unofficial, I'd like to be able to revert back.

I haven't yet unlocked the bootloader or installed TWRP. I don't want to start this process before I know I can go back. I want to make sure I understand what exactly backs up the stock rom so I can flash back if I need to. And I don't know if I'm backing up the factory version, or the version with the changes I've made.

I've removed some system apps from my phone, though I think they return with a factory reset. And I think this is causing a problem with moviepass. Not sure what it needs to not crash, but it is crashing whenver I try to open it. So I thought screw this, I might as well go with a custom ROM at this point. I'm not yet familiar with magisk and the whole game of playing hide and seek with safetynet, it seems that devs keep having to update and create workarounds. I gather magisk roots the phone and hides root.... And safetynet checks a bunch of other things too. It's kinda unclear. I kinda don't want the phone rooted because it sounds like being logged as the admin user on windows. Or at least to have it off and turn it on or log in at will is ok. I guess since I'm already having issues with moviepass I might as well just go with a custom rom. I've been wanting to anyway. I just want to make sure I have a clearer understanding first.

My thing is that from searching around and experimenting I only have a very fuzzy understanding so far. I am not a programmer, I have done some web dev stuff, I have some ideas conceptually from working with javascript, which I am very poor at, however really getting what's going on is a little more difficult when I'm trying to glean it from programmers who are talking on a level where they have assumed knowledge that I don't have.

Yet I'm not going to stay with stock, like the other user suggested, I can't help but tamper with things, because I like to have more control over my phone. I just try to make sure I know I can undo anything I do before proceeding.

I have already read a bunch of stuff and experimented with uninstalling system apps pm uninstall -k --user 0 packagename on a factory reset I think they return. I have read how to unlock the bootloader using adb but it sounds like I will end up bricking the phone without the right custom kernel. I haven't found what kernel I'm supposed to use yet, and I'm not really sure yet what the kernel is really, but it sounds like it would be fun to do. I'm just trying to carefully gather the right info before I try something. I might try this if it looks feasible, or I might go the regular way. It really depends. And I don't know how to back up the kernel or bootloader either. I have a feeling this is not backed up with Stock, or is it?

So yeah, that's why I'm asking about backing up the stock ROM before flashing custom. I don't quite understand what is backed up and from what I read so far it's not clear. It sounds like not everything is backed up. I want to make sure I know what I have and I can revert before proceeding.