Use the 1st method. You don't really need root but you need TWRP installed. And most important S-Off.
And no problem if there is root. OTA will remove root.
After change of MID done, simply reflash stock recovery .. then OTA.
OTA will not run on TWRP or any custom recovery
I have made change MID but when flash stock recovery always failed.
Mine : 4.20.707.6
Stock recovery only available : 4.20.707.7
I can get ready to install OTA update but cannot get success to install due to recovery always shown "red" message even already flash with 4.20.707.7
is there any possibilities to get recovery stock from my phone?
I have TWRP back up.
#edited : I have success flash recovery 4.20.707.6 found on other thread but installation failed in middle with shown red triangle on stock recovery. Have been repeat 2x but no luck.
I will try back from ruu 1.29.707.3 and see what happens OTA update after change MID to 714000.