[OnePlus 8T Guides, News, & Discussion] craznazn:
*** Use this at your very own risk.

*** You will lose all data

*** Backup your working modem and persist, just in case

*** Read the entire post and follow the steps closely before asking for help. Post all error messages and steps you took. Screenshots and MSM logs will be best.

!!! I have officially retired my 8T, and can no longer provide additional support on this device !!!​

It's finally here! A MSM tool that will convert your T-Mobile OnePlus8T+5G to EU KB05BA. From here you can local upgrade to any OOS flavor you want. This gives you Local Upgrade option, faster upgrades, open betas, dual SIM, and more! In fact, after conversion, you can unlock the bootloader without the unlock token (still need to be SIM unlocked, but in case you don't want to wait for the unlock token or if OnePlus's website is broken)!

If you are still SIM locked, you lose the Unlock app for when your device becomes unlocked, it's only available in the stock TMO ROM. If you want to go back to TMO ROM at any point, flash back with the TMO MSM: https://xdaforums.com/t/op8t-oos-tmo-kb09cb-unbrick-tool-to-restore-your-device-to-oxygenos.4180981/

Steps:

Download the MSM Conversion package:

AFH

MD5: 5ddb543c8a5e7587e0b2ad24d2025e77

Run MsmDownloadTool V4.0.exe (Windows 7 users may need to run the win7 version included)

Select User type: "Other" and press Next.

Press "Start". Don't mess with the default settings.

Put your phone in EDL mode.

adb reboot edl

or completely turn off your device, hold vol up + vol down and plug in the cable.

Wait about 5 minutes while it works.

Done! If you keep the bootloader locked and run it stock, the About Phone page will be missing some fields.

If you run into any MSM tool issues, most likely you have a driver problem. See the FAQ in @Some_Random_Username's post

Instructions to Bootloader Unlock a SIM locked device:

In ADB:

adb shell pm uninstall -k --user 0 com.qualcomm.qti.uim

Reboot

Go to dev settings and enable OEM Unlock

Reboot to bootloader

fastboot oem unlock

No unlock.bin needed

Old fastboot method

*** Know how to use the MSMTool, Don't start before figuring it out.

*** DO NOT ATTEMPT THIS IF YOU ARE NOT FAMILIAR WITH THE STEPS DESCRIBED IN THIS GUIDE

* The steps in this guide will convert your TMO KB2007/KB05CB to Global 11.0.5.6.KB05AA, or EU 11.0.3.4.KB05BA

* NR and LTE bands are flashed in nvRAM, not in modem.img or any other partition. You cannot get global bands by flashing a global ROM, nor can you lose TMO bands by flashing another ROM.

* Instructions are the same as running any other MSM unbrick tool.

* You can use this guide to convert to your own variant by extracting payload and flashing from a full OTA. See manual instructions towards the end.

* Use the latest platform tools: https://developer.android.com/studio/releases/platform-tools, https://xdaforums.com/android/general/tool-adb-fastboot-installer-tool-windows-t3999445. DO NOT USE MINIMAL ADB, it has not been updated for years and will cause a crash where you'll need to MSM back to stock.

* Make sure your drivers are up to date. This guide will not walk you through setting up platform tools or updating drivers. When encountering fastboot issues, make sure to include the output of fastboot --version in your post.

* Do not ask for OTAs, MSMs, or anything else not related to the steps described herein. There are plenty of threads around for those.

* This guide does not pertain to Cyberpunk conversion. See other threads.

* This guide converts you to an older firmware so you can take a FULL OTA via Oxygen Updater. Do not skip this step if you want a stable build.

Steps to convert your device to Global or EU

As simple as possible:

You need your device bootloader and SIM unlocked. Follow the instructions here (It says 6T, but applies to all OP devices): https://support.oneplus.com/app/answers/detail/a_id/588/~/how-to-unlock-bootloader-for-oneplus-6t-(t-mobile-edition)

Download and unzip the conversion package:

Global 11.0.5.6

EU 11.0.3.4

Boot to fastbootd.

From adb:

adb reboot fastboot

From fastboot/bootloader:

fastboot reboot fastboot

If you are having trouble booting into fastbootd, and have a FC number at the bottom of the bootloader screen, you'll need to MSM to factory first.

[*]You should be at a screen that says "fastbootd" on top. DO NOT CONTINUE IF YOU ARE NOT HERE. SEE HIDDEN FOR AN EXAMPLE.

Execute "flash_all.bat" for Windows, or "flash_all.sh" for Linux, from the unzipped directory from step 2 as cwd.

Optional: Flash magisk'd boot

fastboot flash boot boot_magisk_patched.img

Reboot into recovery, and wipe everything.

Once fully booted, download Oxygen Updater, set your device to OnePlus 8T of your regional choice and local upgrade to the latest OTA of your regional choice.

Optional: You can re-lock your bootloader at thois point. DO NOT TRY before the full OTA upgrade above, or you'll have to MSM.

Manually:

Unlock bootloader

Download the full OTA of your choosing

Extract the OTA payload with https://github.com/vm03/payload_dumper or https://androidfilehost.com/?fid=818070582850510260

With the output of the payload as your cwd, execute:

fastboot flash product product.img
fastboot flash abl abl.img
fastboot flash aop aop.img
fastboot flash bluetooth bluetooth.img
fastboot flash boot boot.img
fastboot flash cmnlib cmnlib.img
fastboot flash cmnlib64 cmnlib64.img
fastboot flash devcfg devcfg.img
fastboot flash dsp dsp.img
fastboot flash dtbo dtbo.img
fastboot flash featenabler featenabler.img
fastboot flash hyp hyp.img
fastboot flash imagefv imagefv.img
fastboot flash keymaster keymaster.img
fastboot flash logo logo.img
fastboot flash mdm_oem_stanvbk mdm_oem_stanvbk.img
fastboot flash modem modem.img
fastboot flash multiimgoem multiimgoem.img
fastboot flash odm odm.img
fastboot flash qupfw qupfw.img
fastboot flash recovery recovery.img
fastboot flash spunvm spunvm.img
fastboot flash storsec storsec.img
fastboot flash system system.img
fastboot flash system_ext system_ext.img
fastboot flash tz tz.img
fastboot flash uefisecapp uefisecapp.img
fastboot --disable-verity flash vbmeta vbmeta.img
fastboot --disable-verity flash vbmeta_system vbmeta_system.img
fastboot flash vendor vendor.img
fastboot flash xbl xbl.img
fastboot flash xbl_config xbl_config.img

Replace boot.img with your magisk'd boot if desired

Reboot to recovery and wipe everything

Troubleshooting

Error: "remote: no such file or directory"

You are not in the correct cwd. Fastboot needs to be accessible from the same directory as the .img files, so fix your PATH or make a copy fastboot.exe in the same directory as the .img files

Error: "remote: Flashing is not allowed for Critical Partitions"

You are not in fastbootd. Check step 4.

Error: "Invalid sparse file format at header magic"

Ignore this message, not an error

Special thanks to:

@jwarrior319 for the initial linux script

@cammykool and @awr128 for helping debug some of the steps and clarifying pain points

@radiohead7778580 for a better Global conversion

Fixing the About Phone page

These steps are optional, and will fix the "About Phone" page. There are no performance differences.

You need to rooted with Magisk

Download the fix: here

In the Modules page in MagiskManager, Install the downloaded zip file via "Install from storage"

Reboot, the About Phone page is filled out.

Issues so far (please post if you run into more):

In OOS11, "About phone" page does not work properly.

Use the magisk module above to fix it.

In OOS12, Dual SIM is not supported.

A11 based A12 ROMs support Dual SIM after conversion, use my enable_dsds module.

Unlocked bootloader without unlock_token must be done while in OOS11, as OOS12+ ABL will check that a token is needed