Summary: a recent update to the guacamole instructions, which may not yet be reflected in the Easy Installer tool, have left me uncertain about which models are actually supported & how to get around deadlocks for unlocking the bootloader on any Android version from which /e/OS can be installed.
“Build Versions” was changed from “S (stable)” to “T (dev), R (stable)”. This makes sense considering that some models are being shipped with Android 13, as well as reported inability to unlock the bootloader on the 7 Pro in Android 12.
In last month’s version there was a list of “supported models” which included the GM1917 (North America) but not the GM1915 (T-Mobile USA). The current guacamole page has the list of supported models removed, which suggests that all models are now supported (at least on T (dev)).
In part due to this uncertainty, I have both models of the phone now & wondering the best way to proceed, although each possibility appears to have a different deadlock and I don’t know exactly how this officially compatible phone is “supported”.
On the GM1917, Easy Installer confirms that the phone model is supported but reports the bootloader can’t be unlocked:
fastboot oem unlock reports “device cannot be unlocked due to technical reason” which is a known problem described here.
The usual solution is to roll back to Android 11 to unlock the bootloader there, but the guacamole manual install page insists that the phone be on Android 12 before proceeding.
It could be possible to break this apparent deadlock by following the advice at that third-party page: use MSMDowloadTool to revert to Android 11, unlock the bootloader, and then ZIP upgrade to Android 12, but I hope to get a response first about how much of this is really necessary & whether the GM1915 option is possible:
On the GM1915, Easy Installer says that the phone model is not supported:
Since the guacamole page was recently edited so that GM1915 is not excluded, it seems the Easy Installer might be out of date for its list of supported devices… could anyone please check that?
BUT even if going ahead with the Manual installation, I would still have the same problem as above because it’s on Android 11 and the instructions insist on beginning with Android 12.
And also as in the first case, I’m unsure that upgrading Android 12 (as a requirement for the install procedure) wouldn’t re-lock the bootloader again.
There must be a clear path forward since this is one of the currently only 21 phones to work with the Easy Installer, so it must have a lot of testing behind it. But since this deadlock isn’t described in the documentation please I would like some well qualified advice before proceeding.
The (LineageOS > guacamole) page continues to list supported models of the 7 Pro, even though the /e/OS page has for some reason dropped them. LineageOS apparently doesn’t list the GM1915 because T-Mobile (and Sprint for other OnePlus models as well) have changed the memory partitioning to discourage installation of Custom ROMs.
An essential means of loading different OxygenOS versions, the Oxygen Updater app, is a standard part of OnePlus tooling and specifically it says you should never try to install a custom ROM on the GM1915 or any carrier-made OnePlus unless you expect to brick the phone (I saw this when running this app on the GM1917).
The one way to universally unbrick a OnePlus is MSMDownloadTool, for which the commonly referenced XDA post doesn’t list the GM1915 as a supported model. I don’t know if that means it wouldn’t work, but I wanted to be sure the installation was reversible… since return for the phone in its original condition could be refunded.
In hindsight, the process that seemed wasteful & wrong when I wrote about it above… using MSMDownloadTool to revert to OOS 11, then unlocking the bootloader & then updating to OxygenOS 12 via the third-party Oxygen Updater app… turned out to be the easiest part of the process. The difficult part has been the S builds of /e/OS not working for the OnePlus platform, as described in other threads.
I have a GM1915 that originally shipped with T-Mobile firmware. It was purchased refurbished and with no SIM lock. It originally shipped with Android 9 and upgraded OTA to 10, but never pulled an OTA upgrade to 11. The /e/ easy installer wanted nothing to do with it.
It’s now running /e/ anyway…currently on 1.20-stable, based on Android 11. There’s lots of conflicting information about whether this device is supported by /e/ and on how to get there, but this is the high-level view of how I got it installed.
If you haven’t done so already, unlock the bootloader.
Switch from the T-Mobile firmware image to a carrier-neutral image. I used the firmware available here; it rolls the phone back to Android 9, but I let it upgrade to 11 once it was running. The phone still identifies itself as a GM1915 when you go looking for model information in settings. The tool that blasts the image onto the phone only works under Windows AFAIK, and you’ll need to unlock the bootloader again after it’s done.
Download this TWRP build, but don’t install it. (I apologize for linking a filehost site, but I haven’t been able to find a more authoritative source for a binary download and the author only provides source code through GitHub.)
Download the latest stable /e/ release from here. Save it to a USB-C flashstick.
Boot your phone to the bootloader and fastboot boot twrp.img to run TWRP. Don’t flash TWRP to your phone! While it’s starting, plug in your flashstick. Clear out the data and cache directories (I forgot to do this…see below), then flash the /e/ image onto your phone.
Reboot. Your phone should boot up. Mine didn’t at first, possibly because I hadn’t wiped the data and cache directories…it just stayed at the boot screen forever. I fixed this by rebooting to recovery (TWRP had put /e/ recovery on the phone, and it was working) and using /e/ recovery’s ADB sideload feature to install the image again, this time over a USB connection to my computer.
Once booted up, I checked the model information in settings. It’s now identifying as a GM1917. VoLTE and WiFi calling both still work, at least with T-Mobile (they were working previously with stock firmware). The only thing I’ve found that isn’t currently working are the multiple back-facing cameras; Open Camera only wants to work with one of the back cameras (probably the normal camera, not the wide-angle or telephoto cameras). The pop-up selfie cam works.
Update: I got all the cameras working by downloading the stock OnePlus camera app from here. If you disable the Open Camera port provided by /e/, the OnePlus camera app will be the one that loads when you double-click the power button…still need to figure out how to get the camera app to work without unlocking the phone. (You can use NeoBackup to disable Open Camera.)
thanks for sharing @salfter … from the technical notes on the Oxygen Updater app, the problems with T-Mobile and other carrier versions of OnePlus phones are from unconventional partitioning. It seems therefore your process installs a standard partitioning & that this same approach would likely work for other OnePlus models gimmicked by carriers not to work with custom ROMs.
It’s a shame we can’t mark two “Solutions” in this thread: one for carrier-free and one for carrier-customised phones. But I watch the OnePlus topics here… especially the 7 pro… and will refer people here when that question comes up.
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