HTC One M8 phones can now be manually updated to Android 6.0.1 Marshmallow via TWRP 3.0.0 custom ROM. The ROM offers better design on top of many new features.

TWRP 3.0.0 custom recovery now offers Android 6.0.1 Marshmallow support for unlocked HTC One M8 phones around the world. Although some units have already been updated to the official Marshmallow version, this ROM is for those who would want to get more than what the official version offers.

TWRP 3.0.0 offers the following features:

• Battery Level and Timestamp
• Ability to savecustomrecoverysettings
• Search - Select Current Selection
• Ability to auto restore GAPPS on zip flash (for CM-based ROMS)
• Ability to auto reboot after successful flashes
• Ability to flash multiple zips in one go
• Ability to select which individual partitions to backup, and restore
• Ability to choose compression or no compression backups
• Home - Main Menu
• Menu - Advanced Menu
• Back - Up a Menu Level
• Default partitions to back up
• Default zip folder location
• Default color themes
• Default Time Zone (for more accurate time stamps)
• Zip SignatureVerification
• Zip md5 Verification (looks for file with zipname.zip.md5)
• Some devices utilize their capacitive buttons in recovery
• Compression takes longer

Before installing TWRP 3.0.0 custom recovery, the following reminders and prerequisites have to be noted first:

1.      TWRP 3.0.0 is for unlocked HTC One M8.

2.      Install HTC Sync with full working ADB and Fastboot tool.

3.      Do not use the ROM to other devices.

4.      Back up all necessary data here, including apps, SMS messages, contacts, call history, APN settings and more.

5.      Installing any custom ROM voids product warranty.

6.      Installing any custom ROM induces risk of damaging device. Neither this site nor developers will be held responsible for such damage.

To begin with the installation to HTC One M8, here's a step-by-step guide:

1.      Configure ADB and Fastboot in the PC here.

2.      Connect phone to PC using the USB cable.

3.      Copy then paste downloaded ROM files to phone's memory or SD card.

4.      Download TWRP (twrp-3.0.0-2-hima.img) here and copy/paste it in the android-sdk-windows\platform-tools directory.

5.      Go to Fastboot/Bootloader mode. 

6.      Type in: adb reboot bootloader.

7.      Press Enter.

8.      Wait for the driver to be installed.

9.      Type in: fastboot flash recovery twrp-3.0.0-2-hima.img

10.  Press enter.

11.  Once completed, select Recovery and enter Recovery mode.

12.  Select "reboot system now" from the recovery menu.

13.  Wait for TWRP to be installed.

To verify the update, go to Settings > About phone.