Based on Android 5.1.1 AOSP, CyanogenMod 12.1 stable builds are now available for HTC One M8. The CyanogenMod team has released the first CM 12.1 stable releases for various Samsung, LG, Sony, HTC, and Nexus devices. You can now flash CM 12.1 Android 5.1.1 Lollipop on your HTC One M8 too. Follow this guide for files and steps.
Prerequisites to update HTC One M8 to CM 12.1 Stable Release Android 5.1.1:
- Backup any important data from your HTC One M8 as a complete wipe will be required during the flashing process.
- Install USB drivers for your HTC device. Check out this link.
- Enable USB debugging option on your device: Settings > Development Options > USB debugging.
- Ensure that your HTC One M8's bootloader is unlocked and that you have a recovery tool like TWRP or CWM.
- Your device must be charged to at least 80% of power.
How to update HTC One M8 to CM 12.1 Android 5.1.1 Lollipop:
- Download CM 12.1 Android 5.1.1 Lollipop custom ROM for HTC One M8.
- Also download the GApps package for your device.
Here are the steps to help you update HTC One M8 to Android 5.1.1 based CM 12.1 custom firmware:
- Connect your HTC One to your computer using a USB cable and copy the ROM and GApps zip files to your phone’s SD card root folder.
- Disconnect the USB cord and power off your HTC device.
- Boot your device in the Bootloader mode by pressing and holding the Volume Down and Power keys.
- Follow the on screen instructions and select Bootloader > go to Recovery.
- Once in recovery, perform wipe data task: from the CWM recovery menu, select wipe data / factory reset and confirm the process.
- Also perform wipe cache partition followed by wipe dalvik cache (from Advanced).
- From recovery main menu, select install zip from sdcard followed by choose zip from sdcard. Locate the CM 12.1 Android 5.1.1 custom firmware file and confirm the flashing process.
- Once the ROM is flashed successfully, repeat the above step, but select GApps package this time.
- Return back to main recovery menu and reboot your HTC One M8 into the new custom ROM. First boot takes a good 5 minutes so please be patient.