[OnePlus Nord 2 5G] pankspoo:
All of us knows that we upgraded to OxygenOS 12 stable or beta but OnePlus didn't given roll back package so who are stucked on OOS 12 can now downgrade using this process.

This is downgrade process by using relive dvd based MTK client Tutorial booted using Pendrive on window pc.

Remember to follow this you need some patience and flashing knowledge and risk of bricking device if u don't follow correctly.

If you cannot bear this in mind then please don't follow blindly

This process also works for eu regions if you flashed indian open beta oos12 file.

Windows based MTk client application is available and its very good option but for me it's not detecting the the device so I will create another tutorial soon using that tool.

Requirements:

1) PC with all fastboot ,adb drivers and mediatek vcom drivers installed

3) Pendrive or use separate partation on hard drive

4) download files given below

5) patience and some flashing knowledge is must

Download MTk client relive dvd:

https://androidfilehost.com/?fid=15664248565197177367

Mirror link:

https://drive.google.com/file/d/10OEw1d-Ul_96MuT3WxQ3iAHoPC4NhM_X/view?usp=sharing

How to flash relive dvd in pendrive using Rufus that tutorial can be found here:

https://xdaforums.com/t/relock-boot...2-indian-eu-works-for-any-mtk-device.4370559/

Download Oxygen OS 11 firmware backup choose latest as per your device model

Indian DN2101 EU DN2103 and PACMAN)

Extract and save to pc harddrive/relive dvd in PC/laptop

https://gist.github.com/Giovix92/c7e69123dbc51adf3f3a26f9c3c0208e#backup-zips-links

DOWNLOAD PRELOADER BIN FILE:

INDIAN (copy and save it to pc in separate folder)

https://drive.google.com/file/d/1E2yL8uJA7tubHHlqHKkHkJffcCUrllAl/view?usp=drivesdk

EU regions (unzip and take out bin file)

https://xdaforums.com/attachments/preloaderdump_stock-zip.5597685/

Notes :

1)Keep one Harddrive on pc free of space above 30GB

2) you will loose all data so keep full backup

Disclaimer

I am not responsible for anything happens to your device your device your responsibility!

Steps:

A) Baking up the OOS 12 firmware and preloader

1) first keep your pc powered off

2) connect relivedvd iso pendrive and power on the pc and while booting repeatedly press boot menu key fo your pc model you will get about boot menu key info in google search

3)u will get boot menu from there select connected usb pendrive

4)now u will see mtk client relivedvd boot option select first one

5)phone will boot to xubuntu which is nothing but mtk client ready to go environment

6)Now go to file manager on dextop create backup folder to backup your current oos12 name it as you wish.

Remember create this folder in HDD which has more than 30gb space

7) create another folder to take backup of preloader of oos12 in same folder.

8)now trasfer extracted oos11 firmware in same hdd which has all images file.

9)now create seperate folder to save preloader of oos 11 and trasfer the boot1.bin( preloader file) in this folder which we have to flash later.

10)now open mtk client app which ia available on pc dextop

11) take phone in hand power off it, connect one end of usb cable to pc don't connect another end to phone first long press vol up+ down and connect phone to pc keep buttons pressed Until some connection activity of moving circle will be seen in mtk client

12) if it's seen immediately release the buttons now you gets read Partation tab in the mtk client

13)tap on read Partation and select the backup folder you created in hdd.

While selecting the hdd you need to go to computer>media> user there u see all hdd select the hdd where u placed the backup folder.

14) immediately after selecting the folder backup starts ,you will see progress bar at bar in mtk client this will take 25min or more out 2 hr as per your pc model

15)now you gets 100% notification after backup completion now go to flash partation tab and select read preloader

Now select the folder you created to save the preloader file and tap save button from to right corner.

Your preloader for oos12 will be get saves to pc

B) flagshing oos 11 firmware

1) Now go to write partation tab and tap select from directory button

And locate the extracted partation folder.

all paratations automatically gets settled to respective tab in mtk client.

Remember some partation are empty like nvdata, protect and persist don't worry still our device will work

2)tap write partation tab and flagshing starts once done you get 100% progress bar in mtk client.

3)now we need to falsh preloader go to flash tool tab now tap write preloader

Select the preloader from folder where u saves the downloaded from download section.

4)tap open tab from top right corner but this time nothing happens in progress bar and mtk client will gets freeze.

Don't worry our work has done here.

5)now remove usb cable from device and long press vol up+power

6) phone will boots to recovery there tap wipe and format data and your phone will boots to oos12

7) check about phone and see all things working or not like FP, CAMERA etc.

Very imp trouble shooting :

After falshing oos 11 firmware and when you boots if you gets corrupt boot image screen then long press vol up+down +power

Phone will boot to fastboot mode

Now open terminal app on dextop ( or use windows cmd if it's not detecting)

Then reboot back to fastboot type

Fastboot flashing unlock

Press vol up on phone

Now in terminal type fastboot reboot

✌️🙏😃