How To Guide LE2127 OnePlus 9 Pro Custom ROM (T-Mobile)

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Mar 14, 2018
And that's way my TMobile convert to eu. No need to eu to MSM conversation And I can update via system updater. No need to flash modem after ota. I can enjoy stock eu ROM without any problem. Am I right?

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    I am seeing a lot of folks who are still (year later) unable to enjoy custom ROM with T-Mobile devices, so I wanted to quickly post this easy method for enjoying your device with FULL DATA. If you are using a T-Mobile branded OnePlus 9 Pro and have accepted all normal OTA updates as of 9/8/22, you should be on C.19 firmware.

    Assuming you have already unlocked your bootloader, you can safely upgrade to EU C.62 firmware found at:

    I completed this process while already on Nameless but it should work for others too. No more dodgy modules, hacked MSMDownloadTools or sorta working phones. Note, firmware and local updates are NOT the same. You are not cross-flashing to an entirely new software but ONLY required firmware modules for latest custom ROMs. Hope this helps!

    P.S. if you receive any error while sideloading your new firmware, DO NOT unplug or reboot your phone. Repeat the process until it's completed successfully.
    The Tool All In One is a great tool with many uses. You can choose the OP8P and it will work for OP9P. My question is will this really work side loading C.62 or C.63 on Le2127 and not lose data. I still have yet to read a clear guide on doing this. Also there's a lot of us that still use the TMO 9 Pro but I don't see anyone responding to this thread sharing that it really works. It would be nice but I'm not even gonna try until I know for sure that it really does work !
    You can't help folks that don't want to help themselves.
    My system update is showing c.17 as the latest update. I can't seem to get c.19. Would switching to eu firmware delete user data too?
    Appreciate this post. Do you plan on keeping this updated as EU gets updates?

    I'm going to keep this brief since I've spent a lot of time on it today and need to go touch some grass and look at trees, or something.

    I couldn't do much in the way of backing up, so I went ahead with LineageOS. Having sim and bootloader already unlocked, there were no issues. My phone was on C.17 and I couldn't get to C.19 after some trying, so I gave that up. Probably a moot point since I ended up flashing a new ROM anyway. There were a couple of hiccups in the road, some of my own making. I installed the official LineageOS ROM and immediately remembered that I had meant to install microg for LineageOS since that's my setup of choice atm. It took my a while to get that straightened out, what with downgrading problems and all. Then I lost touchscreen. Went back and reflashed everything, but this time with microg recovery as well, and I was back in business. Now this gets us to the point that is germane to this thread:

    I rebooted, sideloaded the C63 firmware on top of the setup I just mentioned. Rebooted again, dropped in a TMO SIM and everything seems great. 5G and calling are working fine. No obvious problems. It boots and runs, it is not bricked. Having said that, I haven't spent much time using it, so that's all I have to report for now.