HTC already announced last year that One M7 units will no longer be updated to any Android version. However, custom ROMs are available for the device to have a glimpse of what Marshmallow can give.
HTC One M7 can now be updated to Android 6.0 Marshmallow using the Resurrection Remix custom ROM. On top of some official Marshmallow features, the ROM brings several of its own new features and improvements particularly in customization and battery.
The device runs on Android 5.1.1 Lollipop before software updates were terminated for the phone. With Resurrection Remix, the custom build will offer toast and list view animation, new clock color customization options, exclusive pitch black theme, network traffic monitor, and battery and performance improvements.
Surprisingly, the developers behind the ROM also brought CyanogenMod's CM13 features like network traffic monitor and battery mods.
Before downloading and installing the custom software, it is important to take note that only GSM models of One M7 will be eligible for the update. Using the ROM to other devices might only lead to their dysfunction.
Also, proceeding with process will make device warranty null and void. HTC will no longer release any software updates to the device.
Before going any further, make sure device is rooted and has enough storage space. Back up necessary data using Clockwok Mod (CWM) Recovery or TWRP. Also, enable USB Debugging in the PC so that the device will be recognized. Finally, charge up phone to at least 80%.
Here are the steps:
1. Download Resurrection Remix Marshmallow ROM and Google Apps on the PC.
2. Connect device with PC using USB cord.
3. Copy downloaded files into the phone's SD card memory.
4. Copy boot.img file in the android-sdk-windowsplatform-tools directory
5. Turn off the device and disconnect from the PC.
6. Perform Bootloader mode.
7. Go to android-sdk-windowsplatform-tools (on the PC).
8. Open Command prompt and type in: 'fastboot flash boot boot.img' and press enter.
9. Type: 'fastboot reboot' and follow instructions displayed on the screen.
10. Select BOOTLOADER option to enter Recovery Mode.
11. Clear the phone memory, by choosing 'wipe data/factory reset'.
12. Clear the cache memory by selecting 'wipe cache partition'.
13. Return to the ClockworkMod recovery
14. Choose 'advanced' and tap 'wipe dalvik cache'.
15. Navigate back to the main recovery screen and then tap 'install zip from SD card'.
16. Tap 'choose zip from sdcard' and go to Android 6.0 Marshmallow ROM .zip file in SD card and enter the installation process.
17. Repeat the procedure for installing Google Apps.
18. Navigate to '+++++Go Back+++++' and re-start the device by opting 'reboot system now' seen in the recovery menu.
Check software to Settings > About phone.
