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.
Connect to phone via adb
- Install adb on an Ubuntu Linux PC.
apt install android-tools-adb
- Before and after plugging in the phone to the PC, type
If phone is not seen, try plugging 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
* daemon not running. starting it now on port 5037 * * daemon started successfully * List of devices attached XXXXXXXXXXXXXXXXXX device
If the last line says offline, approve the debugging request on the phone.
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 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!)