So I guess I need to install twtp and root the phone first.
I went thru this popular route, like here:
http://guidebeats.com/2015/09/10/gui…-mobile-lg-g4/
Download one click twrp for 10n, went thru flashing ending up with "twrp is successfully installed, remove battery etc"
But when actually going to recovery to flash SuperSU and click yes two times, it actually erase everything, no twrp. My guess is that regardless the statement TWRP was not actually installed properly.
How should I proceed? Should I try manually go thru bat file commands to install the recovery manually? Or what is my other option? As I said, I need stock marshmallow , don’t actuslly need rooted phone or custom recovery unless necessary.
Ps. Trying to think what possibly went wrong. I installed two kinds of lg drivers, have OEM unlock checkbox and USB debugging. I can see my device thru "adb devices", and phone reboots once to upgrade firmware mode during batch file execution. Though the phone is saying do not disconnect cable upgrade is in progress, nothing happens and the script is saying twrp is installed successfully. So I just disconnect and remove battery