You can now update your HTC One M8 to Android 6.0 Marshmallow. No, it is not an official Sense update by HTC but it is the most popular custom ROM for Android devices, CyanogenMod 13. The HTC One M8 has a 5.0″ Full HD screen, Snapdragon 801 SoC with Adreno 330 GPU, 2 GB RAM, 16 or 32 GB of storage, dual 4 MP main cameras and a 5 MP front camera, and a 2600 mAh battery.
HTC updated the One M8 from Android 4.4.4 KitKat to Android 5.1.1 Lollipop and is working for the official Marshmallow update. Meanwhile, you can give CyanogenMod 13 a try. It is pure stock Android without a single hit of Sense UI. The experience is similar, if not the same as on a Nexus device. And here’s how to install it.
How To Install CyanogenMod 13 on HTC One M8
As with every other ROM installation, you need a custom recovery. Make sure you have installed the latest version of your preferred custom recovery on your HTC One M8. Then, download CM13 for One M8 and after that download Google Apps.
1. Download CM13 and Google Apps and move them to your HTC One M8.
2. Turn the phone off and boot into recovery such as TWRP.
3. Make a full system backup before you wipe data or flash the new ROM.
4. Wipe data, cache and dalvik cache.
5. Flash CyanogenMod 13 ROM file and then flash Marshmallow Google Apps.
Now all you need to do is to restart your HTC One M8 and you will be good to do. Enjoy the Marshmallow experience on your M8.