G4 Rooting and OS updates

[lotus1922]

I am new to rooting and have a rooted LG G4 to play with (i.e. not my primary phone, so nothing important will be lost if something goes wrong). It came with Lollipop on it, but I want to try more recent versions on it. I understand that upgrading the OS prevents you from rolling back to a previous version even with a factory reset. But would it be possible to flash a pre-update system image and get back to the original OS that way?

Thanks!

 

[Rukbat]

No. The phone sets "stop locks" at various versions, and you can't go back past that. (They're hardware fuses - once blown, there's nothing you can do.)

And you can't update a rooted phone. You have to unroot it, update it, then reroot it. (Once you get to 6.0 (Marshmallow), you can use Magisk to root, which makes unrooting and rerooting a lot easier.

 

[Mooncatt]

Just a heads up that the LG G4 had a design flaw that makes it prone to a bootloop. It's a hardware defect with the soldering, so there nothing short of replacing the main board to fix it (and it'll likely happen again anyway). It's good that this won't have anything important on it, but keep in mind that when the bootloop hits, it's pretty much done for.