I am still playing around with alternate ROMs for Android devices, and I recently came across CarbonROM. I had some issues getting it installed (more due to me than the ROM itself) and so I thought I’d post my steps here.
I was looking for a ROM that focused on stability and security, and Carbon seems to fit the bill.
While I have a lot of experience playing with ROMs, I hadn’t really done it on handsets with “Seamless Update“. In this case there are two “slots”, Slot A and Slot B, and this can cause a challenge when installing a new operating system. This procedure worked for me (with help from Christian Oder via the CarbonROM community on Google+).
- Install latest 8.1 Factory Image
This may not be required, but since I ran into issues I went ahead and installed the latest “oreo” factory image. I had already upgraded the phone to Android 9 (pie) and thought that might have caused the problems I was having, but I don’t think that was the case.
- Unlock the bootloader
This is not meant to be a tutorial installing alternative ROMs, but basically you go to Settings -> System and then locate the build number. Click on that a number of times until you have enabled “developer mode” then go to the developer options and unlock the bootloader and enable the ability to access the device over USB. Then boot into the bootloader and run “fastboot flashing unlock” and follow the prompts on the screen.
- Boot to TWRP using image
In order to install an alternative ROM it helps to have a better Recovery than stock. I really like TWRP and pretty much just followed the instructions. Using the Android Debugger (adb) you boot into the bootloader and run TWRP from an image file.
- Install TWRP zip
Once you are running TWRP, install it into the boot partition from the .zip file. Use “adb push” to put the .zip file on the /sdcard/ partition.
- Reboot to Recovery (to make sure TWRP still works)
- Factory reset and erase /system
Go to “Wipe” and do a factory reset, and then “Advanced Wipe” to nuke the system partition.
You will also want to erase user data at this point. Once I got Carbon to boot it still asked me for a password which I assumed was the one I set up in the original factory install (you have to get into the factory image to unlock the bootloader). I went back and erased all of the user data and that did what I expected, so you might want to do this at this step.
- Install Carbon
Use “adb push” to send the latest Carbon zip file to the /sdcard/. Install using TWRP.
This is the point where my issues started. The next step is to reboot back into recovery. You have to do this so that the other Slot gets overwritten with the new operating system. However, with the Carbon install TWRP was overwritten and that hung the device when I tried to reboot into recovery, so
- Re-install TWRP
Use “adb push” to load the TWRP .zip file again and install it while you are still in TWRP, then
- Reboot to recovery
This should get Carbon all happy on your device as it will be copied over into the other Slot. If you try to boot into the system before doing this bad things will happen. (grin)
- Install GApps (optional)
Now, if you want Google applications you need to install a GApps package. I like Open GApps and so I installed the “pico” package. One thing I am experimenting with here is seeing if I can use a minimal amount of Google software without giving Google my entire digital life. The pico package includes just enough to run the Google Play Store.
This is optional, and if you just want to run, say, F-Droid apps, you can skip this step, but note I’ve been told that you can’t add GApps later, so if you want it, install it now.
- Reboot into the System
If everything went well, you should see the Carbon boot screen and eventually get dropped into the “Welcome to Android” Google sign up wizard. Follow the prompts (I turn off almost everything but location services) and then you should be running CarbonROM with a minimal amount of Google-ness.
The first thing I tried out was “Pokémon Go“. Due to people cheating by spoofing their GPS coordinates, Pokémon Go leverages features of Android to detect if people are running an altered operating system. I’ve found that on some ROMs the application will not work. It worked fine on Carbon and so I’m hoping I can add just a few more “Google” things, like Maps, and then use F-Droid for everything else.
Note that I didn’t “root” my operating system. When you boot into TWRP you can access the entire device with root privileges so I never feel the need to have root while I’m running the device. Seems to be a good security practice and it also allows me to still run Pokémon Go.
Many thanks to the CarbonROM team for working on this. I’m eager to see how soon security updates are released as well as what they do with Android 9, but it looks promising.