[SuperSU] gottlasz:
Detailed description

Systemless root with SuperSU on devices with non gzip compressed ramdisk bootimage

0. Download rce_univ.zip from here: http://viid.me/qir1u5 and download SuperSU (latest or there are some cases that requires earlier versions): https://xdaforums.com/apps/supersu/stable-2016-09-01supersu-v2-78-release-t3452703 and put them on your sd card (external sd card is usually necessary since sometimes TWRP cannot decrypt your data partition/internal sd).

1. Unlock your bootloader

1.1. Additional step for those who has no "...device corrupt..." message during every boot up after unlocking bootloader on Marshmallow and some Lollipop devices(*)

- Boot into TWRP

- on the keep system read only? screen of the TWRP let it allow modifications (swipe!)

- reboot to System

- from now on you should have the message at every boot up

2. Boot into TWRP

- cancel decrypt data

- keep system read only

- go to Backup -> Backup your boot image! Maybe it comes handy later.

- go back from backup to install and install rce_univ.zip right after install SuperSUxxx.zip and then rce_univ.zip again.

- do not wipe anything during and after this step, just reboot! (this might take a while and a few bootloops...)

Video guide: http://viid.me/quIbOi

(3.) Verified boot?

In case of soft brick (or if you're sure you need the proper signature in the end of your boot partition - cos your device has verified boot) try flashing Chainfire's Boot image signer as a very last step before rebooting from TWRP:

https://xdaforums.com/android/software-hacking/signing-boot-images-android-verified-t3600606

(*) on some devices if there is no "device corrupt" message at every boot up after bootloader unlock then anything you do or change in your boot image or system partition your device will not boot up anymore but turning off right after showing you that device corrupt message.

but if you do that trick as written in step 1.1 and that message appears at every boot up then most likely you're goot to go...

You can find some video guides on my thread for the above steps: https://xdaforums.com/lg-k10/how-to/friendly-root-method-lg-k8-k10-t3531223

Pricniple of the installer - rce_univ.zip

What the script does:

Install rce_univ.zip before SuperSU:

1. Finds the boot partition (same way as SuperSU)

2. Dumps the boot image and unpacks it

3. Determines the format the ramdisk was compressed in

4. Uncomresses it then recompresses to gzip (so SuperSU can handle it).

5. Repacks the boot image and flashes it back on boot partition

Here is where you install SuperSU

Install rce_univ.zip after SuperSU:

1. Finds the boot partition

2. Dumps the boot image and unpacks it

3. Reads back the original format of the ramdisk compression

4. Uncomresses it then recompresses the ramdisk with the original compression method(so now the device can handle it).

5. Repacks the boot image and flashes it back on boot partition

As about me:

I was not a complete noob when i started it however it took a lot of effort and time. If you care to understand a bit more what it's about and you want to follow my struggling this is where it started (you can click through the threads):

https://xdaforums.com/apps/supersu/supersu-v2-66-installed-lz4-compressed-t3296508