Note: Since CyanogenMod shut down and forked to LineageOS, so far only LineageOS CM14.1 (Android 7) has been released. Older phones/tablets may not be supported by LineageOS.
To upgrade from CM11 to CM12.1, you will need to first backup your phone and be sure you have SafeStrap of at least version 3.75.
This procedure assumes you’re generally familiar and comfortable with installing alternative OS on your Android device and are fully prepared to risk bricking your phone or having your phone get buggy when you might need it.
Connecting to your phone via adb
First of course you need to have your PC with a working adb installed. We assume an Ubuntu Linux PC.
sudo apt install android-tools-adb
Do you see your phone after plugging it in to your PC when typing
If not, try plugging your phone into a USB 2.0 instead of USB 3.0 port (USB 3.0 ports may be labeled SS or be blue in color (some are not blue)).
Add the udev line corresponding to your devices manufacturer and reboot your PC. Unplug/plug your phone and then type
and you should see something like
* daemon not running. starting it now on port 5037 * * daemon started successfully * List of devices attached XXXXXXXXXXXXXXXXXX device
If the last line says offline, open your phone and approve the debugging request (the phone is trying to keep you safe).
Assuming you have already downloaded the SafeStrap APK for your particular phone, type
adb install Safestrap-XXX-v3.75.apk
in about 10-15 seconds you should see
If not, check that you have APK debugging and installation enabled. See the Lineage OS install for your specific device.
Find the SafeStrap app on your phone and when the Superuser prompt comes
up, allow SafeStrap permanent root access.
You will probably see
State: Old Version at the top; click Install Recovery.
After 30 seconds or so you’ll see that you now have version 3.75 installed as per the small text on the bottom left of your SafeStrap app.
Reboot to Recovery and allow the phone to reboot normally.
- Download the CM12.1 nightly for your specific device.
- Copy all the files you want to save off your device, because this partition is going to be wiped!
Push the .zip to your device (will take about a minute) by:
adb push cm-12.1-XXX.zip /sdcard/
Reboot into Recovery, Wipe, back to Home and then Install and navigate to your /sdcard/cm-12.1-*.zip
- After a couple minutes you will see Success and then Reboot.
Note: I found I had to temporarily unplug my USB cord to allow CM12.1 to fully boot for the first time–maybe a coincidence.
Installing Google Play (optional)
You may also optionally install Google Play after installing CM12.1
- Get the latest Google Play build
Then as before do:
adb push gapps-5.1*.zip /sdcard/
- reboot into Recovery and Install this zip (without Wiping!)