calvinistmac, Jul 21, 2016 : Here is version 3.0 of this guide! VERY IMPORTANT, PLEASE READ!!! These instructions will work with all current versions of OOS 4.0 and above, and the open betas. The instructions will work for the Marshmallow versions (3.2.8 and below for the 3, and the 3.5 series for the 3T) as well. I will not support an earlier open beta than the most current one. My guide, my rules. Any usage of the earlier open betas voids any support, period. IF YOU HAVE A 3T, THESE INSTRUCTIONS WILL WORK, BUT YOU MUST DOWNLOAD THE 3T FILES, NOT FILES MEANT FOR THE 3, OR YOU WILL BRICK YOUR DEVICE. DISCLAIMER: I am not responsible for bricked phones or lost data. Please do the appropriate backups of your data and read all of the instructions posted here before you attempt. If you aren't comfortable doing this then don't do it. MORE INFO: If you post here asking for help (which is fine by the way), I may or may not be able to help you. I don't have your phone in front of me to help you troubleshoot and I cannot magically fix it over the airwaves. If you follow my steps to the letter you should be fine. Make sure you don't skip anything, and please read the DISCLAIMER again for good measure. I've had a lot of posts asking for help and I can't help everyone unfortunately. EVEN MORE INFO: I don't look at this thread all day, every day. If you're asking for support from me and don't get it right away that's the reason. I'm sorry for any inconvenience but it's the way it works. I'm a stay at home dad so that takes up most of my day. I do check it when I can though. Again, sorry if any inconvenience has been caused by my lack of appearance and posts here. Fortunately there are plenty of others who peruse this thread that are just as knowledgeable so someone will get to helping you if I don't. WHY YES EVEN MORE INFO: If you want to downgrade back to MM just use the unrooting process I've outlined here with a MM OOS ROM (version numbers are in the red text up top). That being said, here are the instructions (all commands are typed on a computer using a terminal app (Linux or Mac), or Command Prompt in Administrator mode (Windows)): 1. Download the current OxygenOS (Stable or Open Beta) full zip from the OnePlus support site: http://downloads.oneplus.net/ PRO TIP: rename your downloaded file to ota.zip, it'll make typing the commands a bit easier. If you have a OnePlus 3, then download the OnePlus 3 files. If you have a OnePlus 3T, then download OnePlus 3T files. 2. Download the stock recovery for your device: http://oxygenos.oneplus.net.s3.amazonaws.com/recovery_op3.img - OP3 Recovery http://oxygenos.oneplus.net.s3.amazonaws.com/recovery_op3t.img - OP3T Recovery 3. Boot into Fastboot Mode (I believe it's power and volume up, or use the extended boot menu from Android to boot here) 4. Fire up a terminal app or the Windows Command Prompt in Admin mode and make sure you're in the folder/directory where you downloaded the above files on your computer. 5. Type: fastboot devices -- Just to make sure everything is working. If you see a serial number you're golden. If not check all of your drivers (mostly Windows users will have this issue). There are threads on how to install the drivers within the forums. If you use Linux or a Mac you should already know how to get the proper files on there. 6. Type: fastboot flash recovery recovery_op3.img (or recovery_op3t.img if you have a 3T) -- This will flash the stock recovery back to the phone. 7. Boot into the stock recovery and select the install from ADB option. Once you do that the phone will go into adb sideload mode. After that type the following: adb sideload ota.zip. 8. Once the zip is done sideloading, reboot the phone until it gets to the main setup screen. 9. Reboot your phone into fastboot mode (restart the phone, then hold volume up when it's rebooting) then type fastboot oem lock and follow the prompts on the screen. This will erase the phone. The phone will boot into recovery with chinese characters and wipe the phone clean. When it's done it'll reboot. 10. It should boot into stock, unrooted OxygenOS. Congratulations you did it! Enjoy your stock, unrooted device!