How To Guide OnePlus 9 Pro: How to switch between Color OS and Oxygen OS without unlocking the bootloader

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rackis18

Member
Jun 6, 2013
46
4
I'm running ColorOS official last update on LE2123 everything works signal etc bootloader locked
Screenshot_2021-11-26-00-19-11-14_fc704e6b13c4fb26bf5e411f75da84f2.jpg
 

Fatal_Scythe

Senior Member
Here is a lengthy way to get this working on a EU 9 Pro with WORKING SIM card. I just completed my first phone call! Only do this if you know what you are doing and if you are familiar with the concepts of flashing ROMs, using fastboot to flash partitions and possibly using the MSM tool to restore your device in case something goes wrong. I told you.

Steps to switch from OOS>COS on non-chinese OnePlus 9 Pro. Credits to: Telegram user SamuraiTronVC

Note: This whole process will wipe your data.


1. Install Android A12 Beta 1 by OnePlus via Local Upgrade.


2. Once booted into A12 Beta, install the custom Local Update APK that they provide.


3. Install the ColorOS Dowgrade package and reboot.

__________

Here is how to fix the missing network on 9 Pro. I tested it with my own LE2123 EU 9 Pro, but since the A12 DP is working on IN and NA versions as well, should work for everyone. I updated to the latest ColorOS build after step 3, A.08. Don't know if that is required, but do it anyways. The phone has been behaving a bit weird after doing this - e.g. boot loops once, but then it works etc. Not sure if it has to do with steps 4-6, but proceed with caution. Credits to: Myself.

__________

4. Extract the modem.img from the A12 DP using Payload Dumper. I did it already and you can download it here, but feel free to extract the .img yourself.

5. Unlock your bootloader: fastboot oem unlock

6. Flash the modem.img: fastboot flash modem modem.img
Hi, I'm kinda stuck at the 1. Step already, System-Update just says "Update Installation failed." when trying to install the A12 Beta.

Is there any specific OOS Version I have to be on? I tried on 11.2.8.8 and 11.2.9.9 but both times it fails with the error above.

Thanks in advance. ^^
 

peking_man

New member
Dec 13, 2021
1
0
Planning to buy a OnePlus 9Pro here in China - apologies for what is probably a dumb question, but to convert from ColorOS to OxygenOS is it still necessary use the downgrade ROM process? Or if there is a newer Oxygen version compared to the one the phone comes with, can I just use a direct local upgrade process?

I understand that when the OnePlus 9/Pro was first released the downgrade route was necessary, just not sure if that is stlll the case. I last did this 4 years ago with a OnePLus5 - and it seems some things have changed since then ...!
 

prembhullar

Member
Jan 15, 2016
27
0
Can anyone please help VoLTE don't work for me..when I first bought this device model was le2125 and I went to color is and now even model has been changed and VoLTE don't work.
Screenshot_20211227-081729.jpg
 

Annki81

Member
Dec 30, 2021
6
1
Friends, I need help by !

I have an OP9 Pro (V.CN / global rom / ColorOS V11.2 / Android 11), which package should I download to use Portuguese apps and language in Brazil?

Downgrade packages:
Color OS for OnePlus 9 Pro
Oxygen OS for OnePlus 9 Pro
 

Creazybull

New member
Jan 3, 2022
2
1
Tried to do the same way as instructed but still facing verification fail problem. Device is Chinese version of OnePlus 9 Pro with color os!
 
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elchmartin

Senior Member
Oct 17, 2014
175
56
Duesseldorf
Google Nexus 4
Nexus 7
Planning to buy a OnePlus 9Pro here in China - apologies for what is probably a dumb question, but to convert from ColorOS to OxygenOS is it still necessary use the downgrade ROM process? Or if there is a newer Oxygen version compared to the one the phone comes with, can I just use a direct local upgrade process?

I understand that when the OnePlus 9/Pro was first released the downgrade route was necessary, just not sure if that is stlll the case. I last did this 4 years ago with a OnePLus5 - and it seems some things have changed since then ...!
Very interested in the answer to this, too.
Getting my 9pro in 2 days (if everything goes well).

But I am also willing to try anyway.... Will keep you posted ;-)
 

lgv20v30

Member
Apr 16, 2019
18
2
here is my test result .

1. update to the Android 12 then roll back to color os.
2.flash the provided link for Modem ..work ok with4G but no 5G im in the US with the USA model so maybe i need to flash my own modem to work ...
3. Flash the tmobile Modem found on XDA and messup my phone bricked it !! but msm save me .


after flashing the Tmo modem im keep getting Qualcomm dump Crush screen, ....


i get that screen when I first time flashes schwarzerfleck's modem . but after reboot it is fine...

also what I notice is every OTA update will kill the modem u will need to reflash the modem to get
data/call working ...


if anyone would like to chat about this please pm ur telegram we can share our experience.
When you flash modem, were you on Color OS 11 A.8 (as in the original post), 11 A.13 (current incremental update will go straight to A.13) or 12 C.44 ? Thanks. I tried all 3 and all got Qualcomm dump screen on Le2125.
 

thepublocal

Senior Member
May 22, 2019
69
16
Flashed full ColorOS A12 (NOT OOS12) onto my OP9pro last night and have to say I am amazed on how smooth the experience is. Takes about 5 mins to debloat the chinese bloat off of it and its all good.

I am amazed how there aren't other people flashing this on to the device !
 
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lgv20v30

Member
Apr 16, 2019
18
2
Flashed full ColorOS A12 (NOT OOS12) onto my OP9pro last night and have to say I am amazed on how smooth the experience is. Takes about 5 mins to debloat the chinese bloat off of it and its all good.

I am amazed how there aren't other people flashing this on to the device !
Great to hear that. Which variant of OP9pro (EU, IN, NA) you are using ? Which version of A12 (C.44, etc) ? Do you need to flash modem or get root to have network working ?
 

thepublocal

Senior Member
May 22, 2019
69
16
Great to hear that. Which variant of OP9pro (EU, IN, NA) you are using ? Which version of A12 (C.44, etc) ? Do you need to flash modem or get root to have network working ?
EU model (non root) and I haven't actually put a sim in it yet to test network but have read patching modem is simple enough?
 

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    The China variant of the OnePlus 9 series comes with Color OS instead of Hydrogen OS by default, which is not good news for geeks as Color OS has many limitations compared to Hydrogen OS. Recently, OnePlus has officially provided a way to switch between Color OS and Oxygen OS.

    Please note that switching systems will clear all user data, so you better know what you're doing.

    · Switch from Color OS to Oxygen OS

    Download the downgrade package for the appropriate model and system and put it in the internal storage.

    Installation steps: Settings - Software update - Settings (top right corner) - Select installation package - Select the previously downloaded downgrade package - Install now - Install now

    If the Select installation package option is grayed out, it means that you now have a pending system update and you can choose to install or skip it.

    To skip update: Settings - App management - App list - Menu (top right corner) - Show system - Software update - Storage usage - Clear data - OK - Disconnect all network connections

    · Switching from Oxygen OS to Color OS
    Download the downgrade package for the appropriate model and system and put it in the root directory of the internal storage.

    Installation steps: Settings - System - System updates - Settings (top right corner) - Local upgrade - Select the previously downloaded downgrade package - CONFIRM

    Just reboot your device after the installation is complete and have fun!

    Downgrade packages:
    Color OS for OnePlus 9 Pro
    Oxygen OS for OnePlus 9 Pro
    2
    Can anybody share a video tutorial.. It will be very helpful..i am really confused...
    2
    What about volte and 4g+ (carrier aggregation)?
    4g+ and volte work for me but no 5g
    2
    I did it.. but i dont have 5g anymore any ideas?
    OOS 11.2.3.3
    LE2120
    1
    Mod edit - translated by https://translate.google.com/:
    thanks
    **********************
    感谢