[Guide] Oneplus 7T T-Mobile to International Firmware Conversion Explained

thetoady

Senior Member
Mar 7, 2008
148
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38
you're right! switched my primary calling and data sim to t-mobile sim and it worked from overseas in airplane mode and shows the icon on top. of VoWifi. thanks that's very helpful. just had a decently long chat with my parents to test it out. manually switching it when I have to call the US isn't such a big deal.

though when I just tried to reproduce it, it didn't work. so it seems temperamental.
 

Chxc

Senior Member
Nov 7, 2015
53
2
28
you're right! switched my primary calling and data sim to t-mobile sim and it worked from overseas in airplane mode and shows the icon on top. of VoWifi. thanks that's very helpful. just had a decently long chat with my parents to test it out. manually switching it when I have to call the US isn't such a big deal.
I'm glad you got it figured out.

As with manual switching, may I suggest to take a look with the App on play: Tasker. It might have the necessary privilege without system being rooted to automate your switching task. It's a paid app with a trial period, but I personally recommended it, strongly.
 

the_link_8

Member
Mar 28, 2019
19
2
3
You have to use a compatible fastboot.exe binary, I personally used the OnePlus suggested.

If your device doesn't detect the device, please check with your drivers to remedy your situation.
thanks i already did the whole process and now my phone is running the international version.
 
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thetoady

Senior Member
Mar 7, 2008
148
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38
I'm glad you got it figured out.

As with manual switching, may I suggest to take a look with the App on play: Tasker. It might have the necessary privilege without system being rooted to automate your switching task. It's a paid app with a trial period, but I personally recommended it, strongly.
sort of. It works, but is unreliable to connect via vowifi. I have tasker (and have taser setup to enable call recording on each reboot, no root or bootloader unlocking neccessary)
 

Chxc

Senior Member
Nov 7, 2015
53
2
28
sort of. It works, but is unreliable to connect via vowifi. I have tasker (and have taser setup to enable call recording on each reboot, no root or bootloader unlocking neccessary)
It's my personal opinion this unreliability might has something to do with the rather opaque nature of VoWifi hand shake process. Thus, making it harder to anticipate edge cases in tasker.
 

thetoady

Senior Member
Mar 7, 2008
148
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I'm not talkin tasker, I'm talking just doing it by hand in the settins menu, its unreliable to setup, and no idea why its happening. need logs
 

dimelus

Member
Feb 25, 2012
12
0
21
Can someone help me I already tried this multiple times.

I'm on step 8, after I run flash-all.bat (CMD with admin rights) after some steps my phone just boot T-Mobile rom.

If i try to go into recovery(power and vol+) there is a msg saying that the boot loader is unlocked and software integrity cannot be guaranteed and it just boot again in t-mobile rom.


What should I do?

I got this phone from B&H Photo Video as an T-Mobile Unlocked device.
 

Chxc

Senior Member
Nov 7, 2015
53
2
28
Can someone help me I already tried this multiple times.

I'm on step 8, after I run flash-all.bat (CMD with admin rights) after some steps my phone just boot T-Mobile rom.

If i try to go into recovery(power and vol+) there is a msg saying that the boot loader is unlocked and software integrity cannot be guaranteed and it just boot again in t-mobile rom.


What should I do?

I got this phone from B&H Photo Video as an T-Mobile Unlocked device.
CMD DOS environment =/= PowerShell

I have never got this last flash to work on anything other than admin priv PowerShell, neither should you.
 

dimelus

Member
Feb 25, 2012
12
0
21
CMD DOS environment =/= PowerShell

I have never got this last flash to work on anything other than admin priv PowerShell, neither should you.
Just tried with power shell

AfterRebooting into fastboot my phone just go directly to T-mobile stock rom... What should i do now?

If i turn it off and and do power and vol +it just start on t-mobile again...the phone don't go into recovery and my powershell is stuck on WAITING FOR ANY DEVICE.


EDIT:

I managed to get into recovery(power and vol down, and went into advanced options and boot into recovery.

Now Power shell continue to do those things but there are tons of errors. (Screenshoot 6).

After it finished it just bot again on t-mobile
 

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Chxc

Senior Member
Nov 7, 2015
53
2
28
Just tried with power shell

AfterRebooting into fastboot my phone just go directly to T-mobile stock rom... What should i do now?

If i turn it off and and do power and vol +it just start on t-mobile again...the phone don't go into recovery and my powershell is stuck on WAITING FOR ANY DEVICE.
Are you surr you are using the latest fastboot binary?

This is the classic behavior of not starting the final flashing process using the latest fastboot.exe.

Please consider read more into the details of this guide. This stuff is all there.
 

dimelus

Member
Feb 25, 2012
12
0
21
Are you surr you are using the latest fastboot binary?

This is the classic behavior of not starting the final flashing process using the latest fastboot.exe.

Please consider read more into the details of this guide. This stuff is all there.
I'm actually new to all of this...

I download all the files from this topic, used power shell and did the manual commands copying and pasting from step 7.
 

thetoady

Senior Member
Mar 7, 2008
148
4
38
Unreliable in what sense? My curiosity runs amuck, hah.
not enabling reliably or staying connected (which makes me scared to even have it on overseas if I mistakenly call or accept a call without realizing it). If I jump between prefer mobile or prefer wifi, sometimes it enables when it didn't enable before.
 

Chxc

Senior Member
Nov 7, 2015
53
2
28
nope.


I'm trying to download everything again in a different pc...

Yesterday I tried all different guides on this...more than 10 hours trying haha
Just keep trying. The final fastboot.exe flash is a bit tricky. Took quite a bit hair pulling for me to get lucky.

Make sure, you are not suppose to enter the final flash command one by one, they should be queued with a single copy of paste on powershell or batch invocation.

During the final flashing process, you are NOT suppose to see fastboot screen on your device nor you need to touch it until it's all done and boot into the global firmware, during the middle reboot, 7T should display stock recovery screen (even though it's responding to fastboot commands, don't ask don't know)

Again, you are very close. Keep trying and gl.
 

Chxc

Senior Member
Nov 7, 2015
53
2
28
not enabling reliably or staying connected (which makes me scared to even have it on overseas if I mistakenly call or accept a call without realizing it). If I jump between prefer mobile or prefer wifi, sometimes it enables when it didn't enable before.
I definite see your reservation, it's definitely a lot more trickier when hefty carrier bills are involved.

If VoWiFi is perferred, then you should always prefer wifi as roaming mobile is always throttled to 128kbps on T-Mobile at least, not to mention real world roamed network's own congestion.

Additionally, you might be use the notification icons of the ugly VoWifi as some sort of indicator of success, but don't take my word for it. Give it a try yourself.
 

thetoady

Senior Member
Mar 7, 2008
148
4
38
yes, I base it on seeing the icon. And I have 256kbps (one plus plan), but in general my idea would be to use something like tasker to switch the sims around if I'm on wifi or not. so when I go out of wifi, it switches to local sim, when I'm back in wifi, it switches to t-mobile sim for vowifi.

with all that said, the design decision to require vowifi to only work on primary data sim seems to be a terrible design decision IMHO. I really wonder why it's required. especially when on wifi and the data sim isn't actualy going to be actively used.
 

Chxc

Senior Member
Nov 7, 2015
53
2
28
yes, I base it on seeing the icon. And I have 256kbps (one plus plan), but in general my idea would be to use something like tasker to switch the sims around if I'm on wifi or not. so when I go out of wifi, it switches to local sim, when I'm back in wifi, it switches to t-mobile sim for vowifi.

with all that said, the design decision to require vowifi to only work on primary data sim seems to be a terrible design decision IMHO. I really wonder why it's required. especially when on wifi and the data sim isn't actualy going to be actively used.
Could be a just a practical and security vulnerabilities perversion concern to making dropping and switching between unsafe, unreliable alternative Wi-Fi data paths possible by locking your primary data connection as fail safe.

Also, in your opinion, does the plus worth the extra $10 a month for doubling from 128 to 256 mbps for roaming?
 
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