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OP8 IN2017 (TMO) to Global Dual SIM

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Apr 28, 2010
19
9
Has anyone been able to get dual SIM working on their T-Mobile OP8 after flashing to the Global ROM?

I have a dual SIM tray and whenever I insert two SIMs, I get service on the first, and the second is recognized, but refuses to connect to any network. This applies to any second SIM inserted. The IMEI numbers are showing as the same for IMEI1 and IMEI2, but that shouldn't be an issue as far as I can tell.

Thanks!
 

aviator.OO7

Member
Oct 4, 2015
48
3
Has anyone been able to get dual SIM working on their T-Mobile OP8 after flashing to the Global ROM?

I have a dual SIM tray and whenever I insert two SIMs, I get service on the first, and the second is recognized, but refuses to connect to any network. This applies to any second SIM inserted. The IMEI numbers are showing as the same for IMEI1 and IMEI2, but that shouldn't be an issue as far as I can tell.

Thanks!
I have same issue did you find any fix? Please let me know
 

Cmdr_Colstel

Member
Oct 3, 2021
5
1
Follow these instructions at your own risk. I am NOT responsible for you bricking your device. If you are new to this I advise you to do it with someone who is experienced and knows what he/she is doing.

I was recently able to "rebrand" my OnePlus 8 T-Mobile 5G phone from the T-Mobile version to the European version using these steps (I tried with the GLOBAL version but it DID NOT work):

1. Unlock the bootloader. Steps given in:
https://www.oneplus.com/support/answer/detail/op588

2. I was able to to use the MSMTool_instantnoodle_tmo_15_O.06_200411.zip to go back to 10.5.7.IN55CB
(OnePlus T-Mobile Android build) using the method given in (GLOBAL version FAILED for me here) :
Instructions: https://forum.xda-developers.com/oneplus-8/how-to/op8-unbrick-tool-to-restore-device-to-t4093043
Tool: https://androidfilehost.com/?fid=4349826312261823571

3 Repeat Step 1. Go to Step 4.

4. Next, I upgraded to 10.5.9.IN21BA (OnePlus European Android build) by flashing 10.5.9-EUROPE-OnePlus8Oxygen_15.E.18_OTA_018_all_2007160043_913306-FASTBOOT.zip using the method given in:
Instructions: https://forum.xda-developers.com/t/rom-stock-fastboot-op8-stock-fastboot-roms-for-oneplus-8.4084629/
Tool: https://sourceforge.net/projects/fastbootroms/files/OnePlus 8/

5 Repeat Step 1. Go to Step 6.

6. Finally, I upgraded the phone to the latest OnePlus Android version for this phone through System Update to 11.0.9.9.IN21BA (OnePlus European Android build). Now Dual Sim capability is installed but it does NOT show.

7. Relock the bootloader and NOW dual sim capability shows under SIM & Network.

What I don't understand is that the model, IN2017 (T-Mobile), remains the same but when you boot the phone, the T-Mobile logo does NOT show and it boots like a non-T-Mobile OnePlus phone. I expected the model to change to the European model number (IN2013). My goal was to get Dual-Sim working as it has been banned by carriers here in the good ol' USA. My phone now shows 2 sim cards, originally it only showed 1. Now I have to verify what signals it really works with (5G, 4G ?) and if the dual sim capability works.
 
Last edited:

acostmisa

Member
Apr 7, 2016
27
1
Follow these instructions at your own risk. I am NOT responsible for you bricking your device. If you are new to this I advise you to do it with someone who is experienced and knows what he/she is doing.

I was recently able to "rebrand" my OnePlus 8 T-Mobile 5G phone from the T-Mobile version to the European version using these steps (I tried with the GLOBAL version but it DID NOT work):

1. Unlock the bootloader. Steps given in:
https://www.oneplus.com/support/answer/detail/op588

2. I was able to to use the MSMTool_instantnoodle_tmo_15_O.06_200411.zip to go back to 10.5.7.IN55CB
(OnePlus T-Mobile Android build) using the method given in (GLOBAL version FAILED for me here) :
Instructions: https://forum.xda-developers.com/oneplus-8/how-to/op8-unbrick-tool-to-restore-device-to-t4093043
Tool: https://androidfilehost.com/?fid=4349826312261823571

2 Repeat Step 1. Go to Step 3.

3. Next, I upgraded to 10.5.9.IN21BA (OnePlus European Android build) by flashing 10.5.9-EUROPE-OnePlus8Oxygen_15.E.18_OTA_018_all_2007160043_913306-FASTBOOT.zip using the method given in:
Instructions: https://forum.xda-developers.com/t/rom-stock-fastboot-op8-stock-fastboot-roms-for-oneplus-8.4084629/
Tool: https://sourceforge.net/projects/fastbootroms/files/OnePlus 8/

4 Repeat Step 1. Go to Step 5.

5. Finally, I upgraded the phone to the latest OnePlus Android version for this phone through System Update to 11.0.9.9.IN21BA (OnePlus European Android build). Now Dual Sim capability is installed but it does NOT show.

6. Relock the bootloader and NOW dual sim capability shows under SIM & Network.

What I don't understand is that the model, IN2017 (T-Mobile), remains the same but when you boot the phone, the T-Mobile logo does NOT show and it boots like a non-T-Mobile OnePlus phone. I expected the model to change to the European model number (IN2013). My goal was to get Dual-Sim working as it has been banned by carriers here in the good ol' USA. My phone now shows 2 sim cards, originally it only showed 1. Now I have to verify what signals it really works with (5G, 4G ?) and if the dual sim capability works.
even if the two simcards appear, they won't work for you. the second simcard always says "no service"
 

Cmdr_Colstel

Member
Oct 3, 2021
5
1
even if the two simcards appear, they won't work for you. the second simcard always says "no service"
I went to Verizon yesterday with the setup written above and the second sim did register as Verizon with the first card in slot 1 as T-Mobile. The problem was that we only tested it with 5G. 5G did NOT work with both sim cards placed. I should have put my phone in 4G to see if THAT works. I will go to another Verizon store later in the week to see if it will work in 4G with both sim cards. Hopefully it will.
 

Cmdr_Colstel

Member
Oct 3, 2021
5
1
I went to the Verizon store yesterday and they said that I needed to open an account and activate my phone with that account in order for the Verizon service to work. I was under the impression that all you needed was a Sim card with an active Verizon account and a phone with a good IMEI. I asked them to use a spare Verizon card at the store to test it just to make sure it would work. He wanted me to sign up first which I wasn't going to do. I will have to find another store. Am I correct in assuming that you can just use the sim card from another phone and the service should automatically work ? Or do I have to "register" that phone with Verizon ? F%^k Verizon. Thank you.
 

Cmdr_Colstel

Member
Oct 3, 2021
5
1
So I went to the Verizon store yesterday and brought my OnePlus 8 (IN2017 updated with Oxygen OS 11.0.9.9IN21BA European version). I brought it in unlocked and the Verizon clerk told me it was "dangerous" to leave it unlocked and advised me to lock it (of course I did not). I had my phone set to LTE (4G) under network settings and the two SIMs slots were showing with the first one occupied by T-Mobile. The clerk placed a Verizon SIM card on the 2nd slot and the phone recognized it but IT DID NOT work (messages nor calls). So apparently, according to other users over the web, the blockage of service is coming from the carriers (T-Mobile, Verizon, etc.) themselves. They frown upon dual sim capability and until there are enough complaints to make them change their stance they will continue to refuse to provide dual sim service. It may work in Europe and Asia, but here in the US, not a chance. Talk about UNFREE market.