[LG V20 Questions & Answers] yula16:
Been reading this guide here --» https://xdaforums.com/v20/development/dirtysanta-h990-t3624296

despite much of a mess that it is and poorly written in some regards. I can make perfectly good sense of it all, but the commands issued most of them are pretty useless, or don't work as they're instructed to do.

Let me point out some stuff here, cuz I'm trying to work my way through the tutorial to root my LG V20 H990DS (International) btw;

ok so the first part here it explains the following;

in my case here I'm using Linux, not Windows to do this, so things are simpler, the RUNMEFIRST.sh executable literally does nothing, when I can see it clearly is suppose to do something, let's take a look at what that files trying to run;

#!/bin/sh

# runmefirst.sh
#
#
# Created by me2151 on 12/13/16.
#
adb logcat | grep -a dirtysanta

OK, so it's using logcat to see what the phone is doing while piping to grep to watch out for dirtysanta being written to the phone while you have step1.sh running in another terminal instance, when that command completes you're left in ADB Shell of your device. Meanwhile the first shell script doesn't report anything going on, OK that's fine, doesn't matter since it wrote the contents of the required files to the phone, so it's there, as it should and as it's described in the shell script;

#!/bin/sh

# Step1.sh
#
#
# Created by me2151 on 12/11/16.
#
adb push dirtysanta /storage/emulated/0
adb push aboot.img /storage/emulated/0
adb push dirtycow /data/local/tmp
adb push my-run-as /data/local/tmp
adb shell chmod 0777 /data/local/tmp/*
adb shell /data/local/tmp/dirtycow /system/bin/run-as /data/local/tmp/my-run-as
adb shell /data/local/tmp/dirtycow /system/bin/applypatch /data/local/tmp/dirtycow
adb shell

Now this next part, doesn't work at all, because in the tutorial guide, they said to do chmod 777 permissions on "/storage/emulated/0/*" this doesn't work because operation is not permitted by the file owner and group root, there is no write permission to change permissions of that directory structure.

chmod: chmod '/storage/emulated/0/Android' to 40777: Operation not permitted

and yes /storage/emulated/0/ is suppose to be your storage userspace of where you save your files and stuff. Your "virtualized" SD Card space, you have normal read-write access there anyways. The next part of that tutorial says to check the id output from the Terminal Emulator app on Android, and check for the response "untrusted_app", that I do get, if you're doing it through ADB Shell you'll get "context=u:r:shell:s0" instead.

Part 12 of the tutorial has misuse or incorrect command line usage for applypatch, it will not simply execute because the command line usage is incorrect like so;

applypatch /system/bin/atd /storage/emulated/0/dirtysanta

it'll just simply return the following;

usage: applypatch [-b <bonus-file>] <src-file> <tgt-file> <tgt-sha1> <tgt-size> [<src-sha1>:<patch> ...]
or applypatch -c <file> [<sha1> ...]
or applypatch -s <bytes>
or applypatch -l

Filenames may be of the form
MTD:<partition>:<len_1>:<sha1_1>:<len_2>:<sha1_2>:...
to specify reading from or writing to an MTD partition.

obviously the step2 shell script can't do anything because there is nothing to backup, since it's calling to backup the boot images off the device.

So far I haven't been able to find any comprehensive or updated rooting guide for LG V20 H990DS in particular, nothing new worked on seems to popup anywhere as of yet.