Note:
This guide containing the CyanogenMod 12.1 custom firmware and instructions are working only with the Galaxy Note 2 GT-N7100 (International Variant). Check the model number of your Note 2, if it is GT-N7100 then proceed to the installation guide, otherwise not. You can verify the model number of the device from Settings > About Phone.
Before Getting Started:
Create a proper backup of all your existing data and settings on the phone before proceeding to the installation guide using a recommended custom recovery.
Enable USB Debugging Mode on the Galaxy Note 2 by navigating to Settings > Developer Options.
Verify that you’ve properly installed the Galaxy Note 2 USB Drivers on the PC.
The Galaxy Note 2 should be rooted with the latest version of custom recovery like CWM or TWRP installed.
Make sure that the battery level of the Galaxy Note 2 is at least above 80% before going ahead.
Steps to Update Galaxy Note 2 (GT-N7100) to Android 5.1 with CyanogenMod 12.1 ROM:
Step No 1:- First, download Android 5.1 CyanogenMod 12.1 custom ROM (cm-12.1-20150405-UNOFFICIAL-n7100.zip) for Galaxy Note 2 GT-N7100 on the desktop of the PC.
Step No 2:- Plug your device to the PC using its USB data cable and mount its USB memory storage.
Step No 3:- Transfer Android 5.1 CyanogenMod 12.1 ROM .zip file which you’ve already downloaded from the above link, to the root folder of your SD card on the phone.
Step No 4:- Unplug the Galaxy Note 2 GT-N7100 from the PC and power it OFF in order to boot into Recovery Mode.
Step No 5:- Power ON the device while pressing and holding Volume Up + Home + Power buttons at the same time to enter into Recovery Mode.
Step No 6:- While your device is now in CWM Recovery, perform wipe data/factory reset, wipe cache partition and wipe dalvik cache also by navigating to Advanced > Wipe Dalvik Cache.
Note:- wipe dalvik cache will help you to prevent boot loops and other errors while ROM installation.
Step No 7:- Go back to the main Recovery Menu and choose install zip from SD card → choose zip from sdcard.
Step No 8:- Navigate to the CM12.1 Android 5.1 Lollipop custom ROM .zip file which you’ve already transferred to the SD card of your device previously. Select the ROM .zip file using the Power button and confirm the installation to begin.
Step No 9:- installation is completed. From Recovery Menu, reboot your device by selecting reboot system now.
Your Galaxy Note 2 GT-N7100 will be rebooted and may take about 4 to 5 minutes to boot for the first time after installation.
Done! You’ve successfully updated Galaxy Note 2 (GT-N7100) to the latest Android 5.1 Lollipop with CyanogenMod 12.1 ROM.
Let us know in the comments area below if you have any query or trouble while installing this CM12.1 custom firmware featuring Android 5.1 Lollipop on your Galaxy Note 2.