[LeEco Le Max 2 Questions & Answers] unrel:
Explicit intended steps.

After doing some research I think

can be performed with the following steps:

0. Commanders intend: mount system in RW (rewritable) mode:

1. Download minimal ADB and Fastboot.

2. Install TWRP and root on your phone

3. Steps: open adb on pc. Current location = \url{E:\somefolder\Minimal ADB and Fastboot_techbeasts\py.cmd

4. connect the phone with usb to pc.

5. Select mount in TWRP:

6. select \textbackslash system

7. press mount.

8. source for next step: \url{https://xdaforums.com/xperia-z2/help/help-to-mount-rw-twrp-recovery-t3376485}

9. \url{https://askubuntu.com/questions/175739/how-do-i-remount-a-filesystem-as-read-write}

10. \url{https://stackoverflow.com/questions/28009716/how-can-i-remount-my-android-system-as-read-write-in-a-bash-script-using-adb}

11. finally the last link, the following command sequence appears to solve the issue:

# Script to mount Android Device as read/write.
# List the Devices.
adb devices;

# Run adb as root (Needs root access).
adb root;

# Since you're running as root su is not required
adb shell mount -o rw,remount /;

12. Commanders intend: fetch(1) $/system/usr/keylayout/synaptics_dsx.kl$ and edit it.

13. Source used to execute commanders intend: \url{https://xdaforums.com/shield-tv/general/change-3rd-party-remote-key-layout-root-t3548871}

14. steps: adb shell \textgreater enter \textless

15. That shows

~ # <-[6
\end{verbatim}
\item ignore that weird stuff and just immediately after enter:
\begin{verbatim}
cat /proc/bus/input/devices

16. Now you will have a list of connected remote/controller, take a note of the Vendor number and the Product number.

17. ctrl+c to get out of the to me uknown, ~\# thingy

18. adb pull $/system/usr/keylayout$

19. that yielded for my moto G3:

E:\somefolder\Minimal ADB and Fastboot_techbeasts>adb pull /system/usr/keylayout
pull: building file list...
pull: /system/usr/keylayout/qwerty.kl -> ./qwerty.kl
pull: /system/usr/keylayout/Vendor_2378_Product_100a.kl -> ./Vendor_2378_Product_100a.kl
pull: /system/usr/keylayout/Vendor_2378_Product_1008.kl -> ./Vendor_2378_Product_1008.kl
pull: /system/usr/keylayout/Vendor_22b8_Product_093d.kl -> ./Vendor_22b8_Product_093d.kl
pull: /system/usr/keylayout/Vendor_1d79_Product_0009.kl -> ./Vendor_1d79_Product_0009.kl
pull: /system/usr/keylayout/Vendor_1bad_Product_f036.kl -> ./Vendor_1bad_Product_f036.kl
pull: /system/usr/keylayout/Vendor_1bad_Product_f027.kl -> ./Vendor_1bad_Product_f027.kl
pull: /system/usr/keylayout/Vendor_1bad_Product_f023.kl -> ./Vendor_1bad_Product_f023.kl
pull: /system/usr/keylayout/Vendor_1bad_Product_f016.kl -> ./Vendor_1bad_Product_f016.kl
pull: /system/usr/keylayout/Vendor_1949_Product_0401.kl -> ./Vendor_1949_Product_0401.kl
pull: /system/usr/keylayout/Vendor_18d1_Product_5018.kl -> ./Vendor_18d1_Product_5018.kl
pull: /system/usr/keylayout/Vendor_18d1_Product_2c40.kl -> ./Vendor_18d1_Product_2c40.kl
pull: /system/usr/keylayout/Vendor_1689_Product_fe00.kl -> ./Vendor_1689_Product_fe00.kl
pull: /system/usr/keylayout/Vendor_1689_Product_fd01.kl -> ./Vendor_1689_Product_fd01.kl
pull: /system/usr/keylayout/Vendor_1689_Product_fd00.kl -> ./Vendor_1689_Product_fd00.kl
pull: /system/usr/keylayout/Vendor_1532_Product_0900.kl -> ./Vendor_1532_Product_0900.kl
pull: /system/usr/keylayout/Vendor_12bd_Product_d015.kl -> ./Vendor_12bd_Product_d015.kl
pull: /system/usr/keylayout/Vendor_1038_Product_1412.kl -> ./Vendor_1038_Product_1412.kl
pull: /system/usr/keylayout/Vendor_0b05_Product_4500.kl -> ./Vendor_0b05_Product_4500.kl
pull: /system/usr/keylayout/Vendor_05ac_Product_0239.kl -> ./Vendor_05ac_Product_0239.kl
pull: /system/usr/keylayout/Vendor_0583_Product_2060.kl -> ./Vendor_0583_Product_2060.kl
pull: /system/usr/keylayout/Vendor_054c_Product_0268.kl -> ./Vendor_054c_Product_0268.kl
pull: /system/usr/keylayout/Vendor_046d_Product_c532.kl -> ./Vendor_046d_Product_c532.kl
pull: /system/usr/keylayout/Vendor_046d_Product_c299.kl -> ./Vendor_046d_Product_c299.kl
pull: /system/usr/keylayout/Vendor_046d_Product_c294.kl -> ./Vendor_046d_Product_c294.kl
pull: /system/usr/keylayout/Vendor_046d_Product_c21f.kl -> ./Vendor_046d_Product_c21f.kl
pull: /system/usr/keylayout/Vendor_046d_Product_c21d.kl -> ./Vendor_046d_Product_c21d.kl
pull: /system/usr/keylayout/Vendor_046d_Product_c219.kl -> ./Vendor_046d_Product_c219.kl
pull: /system/usr/keylayout/Vendor_046d_Product_c216.kl -> ./Vendor_046d_Product_c216.kl
pull: /system/usr/keylayout/Vendor_046d_Product_b501.kl -> ./Vendor_046d_Product_b501.kl
pull: /system/usr/keylayout/Vendor_045e_Product_0719.kl -> ./Vendor_045e_Product_0719.kl
pull: /system/usr/keylayout/Vendor_045e_Product_028e.kl -> ./Vendor_045e_Product_028e.kl
pull: /system/usr/keylayout/Vendor_0079_Product_0011.kl -> ./Vendor_0079_Product_0011.kl
pull: /system/usr/keylayout/Generic.kl -> ./Generic.kl
pull: /system/usr/keylayout/AVRCP.kl -> ./AVRCP.kl
35 files pulled. 0 files skipped.
37 KB/s (49818 bytes in 1.285s)

20. All those files are for pre-built in controllers that you can connect the the phone, eg xbox 360 controller, snes controller etc. Except for AVRCP.kl and Generic.kl, these are used for the normal phone.

21. Change Generic.kl as AVRCP.kl says AVRCP.kl is not used anymore.

22. Copy the Generic.kl back:

adb root
adb disable-verity
adb reboot
(power down, boot into twrp again)
adb root
adb remount
adb push "layout file" /system/usr/keylayout (becomes in this case:)
adb push Generic.kl /system/usr/keylayout
adb reboot