[Asus Padfone X and S] xdej:
I got root with my personnal open-source files:

# /system/bin/id
uid=0(root) gid=0(root) groups=0(root), context=u:r:init:s0

How I got there:

(1) install Termux from Google Play

(2) in /data/data/com.termux/files/home, put "CrowLock_RC3.zip" and "SuperSU-v2.79-201612051815.zip".

(3) Install version v19 (will be uploaded soon) of https://sourceforge.net/p/gentooandroid/wiki/InstallingInstructions/ using EPREFIX=/data/data/com.termux/usrex.spartacuside/gentoo_armv6l and PLACE_LD=/data/data/com.symli/n/3 following all instructions (that took me half a day, this installs Gentoo on your phone; if you want I can make an easier way). Don't add any package with emerge, this is not needed at this point.

(4) Download twrp_2.8.7.0.rar from https://mega.nz/#!GwRRBBjT!8ms39GK62...aKA816Cg4lsQr0

checksums with sha1sum:

8dc6b577d04fbd05ff31d3dedca7cf51d7bfef22 twrp_2.8.7.0.img

1d784bde5339054ed27ff38fb17e1368f95d6dcb twrp_2.8.7.0.rar

(5) Connect it to a computer, then power Off the phone, keep "vol up" button pressed before it switches off.

(6) If you did not connect it to a computer, press "power" button

(7) the phone powers on, vibrate a bit, you can release the buttons "power" and "vol up".

(8) you now need another computer. If it is a linux computer, install package android-tools , then run, as root: fastboot flash recovery twrp_2.8.7.0.img ; if it is a windows computer, issue the equivalent instruction with fastboot.exe downloaded from https://xdaforums.com/showpost.php?p=62352276&postcount=2 (checksums with sha1sum:

e01c22dc34e915bca88de2c73966b807b2b39f26 fastboot.exe

eb9ce15bebcfb63a5cb4c24913aba76c8d319287 fastboot_and_adb.rar) ; whether you have a mac or no, also download fastboot from https://wiki.lineageos.org/adb_fastboot_guide.html You can ignore the erro "remote: can't flash unsigned image' is actually working": it nevertheless did works.

(9) keep "vol down" pressed on the phone.

(10) on linux, execute: fastboot reboot ; on windows, fastboot.exe reboot I guess

(11) after it vibrates, you can now release "vol down". select "enter recovery mode", then validate with the power button. The phone boots twrp, which is a sort of equivalent of init=/bin/sh on linux.

(12) in twrp, select "keep read-only", then use "install", then select "/data/data/com.termux/files/home/CrowLock_RC3.zip", validate, then repeat steps (5) to (11).

(13) in twrp, select "keep read-only", then use "install", then select "/data/data/com.termux/files/home/SuperSU-v2.79-201612051815.zip", validate, then repeat steps (5) to (11) (if you skips entirely step (13), the phone will not be able to boot).

(14) in twrp, select "advanced", then "terminal command", then select directory /data/data/com.termux/usrex.spartacuside/gentoo_armv6l/usr/local/bin as working directory

(15) execute: mount /system

(16) execute: mv /system/bin/app_process32 /system/bin/app_process.wrapped (you will first need to use backspace to remove characters of previous command, "mount /system")

(17) execute: cp app_process_wrapper /system/bin/app_process32

(18) execute: chgrp shell /system/bin/app_process32

(19) execute: umount /system

(20) use back button three times, and select reboot, then select system.

(21) it should boot normally. It did on my asus padfone S and on my asus padfone S+ (the only padfone with 3GB of RAM).

(22) open tmux, inside it, execute:

ssh -p 64000 root@localhost

(23) you will be asked the root password that you used at step (2)

if you want to add packages, remember to use

ssh -p 64000 xdej@localhost

before using Gentoo's installer:

PORTAGE_BINHOST=http://sourceforge.net/projects/gentooandroid/files/packages/packages emerge --autounmask-write -GKv firefox