[GUIDE] Complete Step-by-Step Convert T-Mobile to Global (or other) firmware

[NorlanBustilloX]

You have to do Part 3 as I believe T-Mobile ROM does not recognize Dual SIM

Okay, Part 3 I get it. But Part 2 is necessary if I do not want/care for dual SIM?

I currently have Android 10, working fine, but I'm not sure if unlocking Bootlader is just for Dual SIM or for something else.

I just want to have Global (IN2015), even if Dual SIM is not there. Should I still do it or can I skip it?

Also, if I have to do Part 2, is OEM Unnlocking the only toggle I need to check, or do I need to activate USB Debugging as well?
Sorry for so many questions.

 

[thattechguy_69]

Okay, Part 3 I get it. But Part 2 is necessary if I do not want/care for dual SIM?

I currently have Android 10, working fine, but I'm not sure if unlocking Bootlader is just for Dual SIM or for something else.

I just want to have Global (IN2015), even if Dual SIM is not there. Should I still do it or can I skip it?

Also, if I have to do Part 2, is OEM Unnlocking the only toggle I need to check, or do I need to activate USB Debugging as well?
Sorry for so many questions.

if you just want to convert to global then just unlock bootloader and flash global fastboot ROM. NOW if you want IN2015 Model number even if you don't use dual SIM? IT is necessary to do the entire process. The model number itself is included to the Dual SIM conversion. With just fastboot ROM only? No. Using the fastboot ROM only changes the ROM itself.

 

[thattechguy_69]

Okay, Part 3 I get it. But Part 2 is necessary if I do not want/care for dual SIM?

I currently have Android 10, working fine, but I'm not sure if unlocking Bootlader is just for Dual SIM or for something else.

I just want to have Global (IN2015), even if Dual SIM is not there. Should I still do it or can I skip it?

Also, if I have to do Part 2, is OEM Unnlocking the only toggle I need to check, or do I need to activate USB Debugging as well?
Sorry for so many questions.

You just need to have OEM Unlock toggle ON

 

[NorlanBustilloX]

You just need to have OEM Unlock toggle ON

Okay. I'll just leave OEM Unlock toggled. Last time I toggled USB Debugging as well. Maybe that's why it failed. I'll do every single step and part. I'll come back in a few hours.

Once again, thank you for everything.

EDIT: Okay, so I tried again and the same issue. When connecting the phone after opening MSM, I clicked Start for the app to look for my phone. I pressed the button combination, and then the device was recognized. No "Enum and Start" options were available. After that, the phone reboots to the green START buttons, and "The device is corrupt" message never appears.

 

[954wrecker]

Is it possible to flash the dual SIM file on a T-Mobile OnePlus 8 that's already unlocked and running global firmware?

 

[NorlanBustilloX]

Okay. I'll just leave OEM Unlock toggled. Last time I toggled USB Debugging as well. Maybe that's why it failed. I'll do every single step and part. I'll come back in a few hours.

Once again, thank you for everything.

EDIT: Okay, so I tried again and the same issue. When connecting the phone after opening MSM, I clicked Start for the app to look for my phone. I pressed the button combination, and then the device was recognized. No "Enum and Start" options were available. After that, the phone reboots to the green START buttons, and "The device is corrupt" message never appears.

Still no luck. I´m still getting the "FAILED (remote: 'Flashing Unlock is not allowed (THW.)') fastboot: error: Command failed" message.

 

[hassaan786]

@thattechguy_69 instead of saying the device is corrupt its loads into fastboot mode please help!!!!

 

[hassaan786]

Still no luck. I´m still getting the "FAILED (remote: 'Flashing Unlock is not allowed (THW.)') fastboot: error: Command failed" message.

I guess we both should get our unlock token from Oneplus

 

[NorlanBustilloX]

I guess we both should get our unlock token from Oneplus

And how do we do that? Is it expensive? I'm stuck exactly where you are.

 

[thattechguy_69]

And how do we do that? Is it expensive? I'm stuck exactly where you are.

Free

 

[NorlanBustilloX]

Free

I'll check that out. I bet it takes days to receive it, right?

Is that the solution for this issue?

 

[thattechguy_69]

I'll check that out. I bet it takes days to receive it, right?

Is that the solution for this issue?

7 days, unlocking using unlock token might be able to

 

[TechForEver]

Because every MSM Tool is tied to a specific version of the device. If you try to use Euro/Global MSM tool, the tool won't let you flash it. Some people know how to modify MSM Tools to make them work on any device, ex: OnePlus 8T TMobile to Euro MSM Tool "no bootloader unlock needed." The problem with this is that no one has made one for OnePlus 8 therefore we have to use this guide to convert to global.

Thanks brother.thank you for great work you have safe many people
Excuse please let me know i have bad pc i ask what would be happens if during flash any file of these in guide.
if the pc shutdown what will happen
just repeat step and reflash or this can hardbrick my phone .

sorry for question

 

[thattechguy_69]

Thanks brother.thank you for great work you have safe many people
Excuse please let me know i have bad pc i ask what would be happens if during flash any file of these in guide.
if the pc shutdown what will happen
just repeat step and reflash or this can hardbrick my phone .

sorry for question

just dont let the pc shutdown just to be safe. this guide shouldn't overload the pc

 

[iMogul]

Is it possible to flash the dual SIM file on a T-Mobile OnePlus 8 that's already unlocked and running global firmware?

Yes, I had unlocked the TMO Variant bootloader and converted to GLOBAL ROM back in 2021 following the first guide that was in this thread. I re-did everything now and have a global ROM with Dual SIM enabled.

 

[iMogul]

I'll check that out. I bet it takes days to receive it, right?

Is that the solution for this issue?

I did not have this issue but I did have a unlock token from OnePlus when I did the conversion to Global ROM around 15 months ago. You can try this route and see if it works. The unlock.ops is supposed to work for locked bootloaders but I cannot verify since mine was already unlocked.

 

[zaq123]

I already have my device OEM unlocked with a token from T-Mobile. I am trying to get dual sim and flash a global rom. I tried this method even though I was already unlocked and I cant get past "fastboot flashing unlock"
Do I need this or I can get Dual sim ?

 

[iMogul]

I already have my device OEM unlocked with a token from T-Mobile. I am trying to get dual sim and flash a global rom. I tried this method even though I was already unlocked and I cant get past "fastboot flashing unlock"
Do I need this or I can get Dual sim ?

You need to do the second step which is the unlock.ops to make the TMO variant a DUAL SIM capable. The dual SIM ( two IMEIs) will show up once you local upgrade the global rom after the 3rd step.

When you say you can't get past the "fastboot flashing unlock" , what do you get ?

 

[henryc333]

I already did a TMO to Global conversion last year and got a two-sided sim tray from aliexpress. Then found out that the second sim slot did not work when I got to Taiwan.

Saw the new unlock/dual-sim step here and decided to start over again. This time around, I just couldn't put the phone in EDL mode without the adb reboot edl. After Part 3 step 3 (flashing Fastboot ROM), my phone hung with CrashDump Mode. Now I needed a non-adb way to enter EDL mode to restart from step 1. IT TURNED OUT THAT I NEEDED A USB-2 PORT for the Qualcomm driver to work.

After several more trials, I substitute the Fastboot ROM here with the one from the "[Guide] Convert to Global [WIP]" thread. That avoided the CrashDump for me and I was able to do system update to Oxygen OS 13 F_13 in many steps and lock the bootloader.

To my surprize, the Dual Sim does work with OxygenOS 13. Thank you OP.

Somehow I couldn't update from F_13 (Oct 2022) to the more stable F_15 (Dec 2022). Ended up have to download the update using "Oxygen Updater" and apply it with "OPLocalUpdate for Android 12" as local update was removed since OxygenOS 12.

Hope someone finds my mistakes and workarounds useful. My experience with Oxygen 13 F_15 is that it is efficient and reliable but it very different from OxygenOS 11.

 

[ANookNewb]

This method does not appear to work anymore. Both flashing the unlock.ops and unlocking via the token first and then flashing the unlock.ops just drops you in the regular fastboot screen with the unlock is not allowed THW error.