HTC One on display at a store. (Reuters)Reuters

Earlier this year, HTC disbanded software update support for the HTC One (M7), as the device completed its two year cycle.

The company, as part of an exclusive HTC Advantage programme for the flagship devices, offers update support for two years, six months more than the rival Android device makers.

The HTC One M7 received its last update Android 5.0.2 Lollipop in February this year.

[Read more: HTC One (M7) Software Update Service Ends with Android 5.0.2 Lollipop; Don't Wait for v5.1 Stability Software, Says Company]

That said, readers who are still hanging on to their HTC One (M7), we have some good news to share. XDA Developer Forum's senior member dd98 has released the CyanogenMod CM13 series custom ROM to the 2013 flagship phone.

It is based on the Android's latest v6.0 Marshmallow and brings Doze power saving feature, faster Chrome browser, more intuitive Now on Tap feature, new security feature, verified boot system, support for more international dialects, a new contextual assistance feature and numerous other features to enhance user-experience on HTC One M7.

Also read: Google Android 6.0 Marshmallow: 7 key features you need to know

However, we would like to remind our readers that this CyanogenMod CM13 firmware is an experimental version, so there are some bugs in it. Users are advised to exercise caution before going ahead with the installation.

Prerequisites (things to remember before installing Custom ROM)

  • This new Android 6.0 Marshmallow custom series has to be installed on HTC One (M7) GSM, AT&T, T-Mobile (m7_u, m7_ul, m7_att, m7_tmo) models only, if tried on other devices, they might get bricked [to check your device model: Go to Settings >> About phone >> model number].
  • Though installing custom ROM improves the device's performance and UI experiences, it makes the company warranty void; the company will no longer be liable to provide updates in future [users can restore warranty by flashing the device with stock-ROM].
  • Make sure the device is rooted before going ahead with custom ROM installation.
  • Installation of custom ROM requires clearing memory in the phone, so make sure to back all the data by installing Clockwork Mod (CWM) Recovery/ TWRP in the smartphone.
  • Make sure USB driver is installed in the PC or else your device (HTC One M7) will not be recognised by the computer.
  • Make sure your device has more than 80% battery, or else there is a chance of the tablet getting temporarily bricked if the installation process is interrupted midway.

[Disclaimer: This procedure is very technical and should be performed by a person with sound knowledge of rooting (or manual software installation) Android devices. If the step-by-step installation process is not followed properly, there are chances of the smartphone getting bricked or being permanently irreparable. IBTimes India cannot be held responsible for any damage or claims from readers if the procedure does not yield the required results or if the smartphone is bricked. Hence, users are advised to proceed with caution.]

Tutorial: Step-by-step Installation Procedure of CyanogenMod [unofficial] CM13 Android 6.0 Marshmallow custom ROM on HTC One M7:

Step 1: Download Android 6.0 Marshmallow CyanogenMod [unofficial] CM13 custom ROM and Google Apps  on to your PC.

[Note: Downloadable CM13 firmware and Google Apps file links are given below]

Step 2: Connect HTC One M7 to PC via USB cord.

Step 3: Place Android Marshmallow zip file and Google Apps files into the phone's memory. [Note: Users are advised to paste the .zip file in SD card root, not in any other folder.]

[Note: Before installing the custom software, be sure that the device must have been rooted and has installed ClockworkMod Recovery tool.]

Step 4: Place boot.img file in to the android-sdk-windowsplatform-tools directory

Step 5: Turn off the device and disconnect from the PC.

Step 6: Perform the regular Bootloader mode sortie, by press holding 'Volume (Down)' and 'Power' buttons.

Step 7: After entering the Bootloader mode (on the phone), go to android-sdk-windowsplatform-tools directory (on the PC) and open Command prompt, then type in: 'fastboot flash boot boot.img' and press enter.

(To enter Command prompt: Shift + right-click >> open Command Prompt)

Step 8: Type - 'fastboot reboot' and press enter. Then, follow instructions displayed on the screen. Select BOOTLOADER option to enter Recovery Mode.

Step 9: After entering the Recovery mode, clear the phone memory, by choosing 'wipe data/factory reset' [Note: use Volume keys to navigate and power button to select options, while operating under Recovery Mode]

Step 10: Clear the cache memory by selecting 'wipe cache partition'.

Step 11: Navigate back to ClockworkMod recovery, and select 'advanced' and tap 'wipe dalvik cache' [Note: This step is optional, but many recommend this procedure so that user will not face boot loops or any other errors in the middle of custom ROM installation]

Step 12: Return to the main recovery screen and then tap 'install zip from SD card'

Step 13: Tap 'choose zip from sdcard' and go to Android Marshmallow ROM .zip file in SD card and enter the installation process. Repeat the same procedure for Google Apps [Note: use Volume keys to navigate and power button to select options]

Step 14: Once done with the installation process, navigate to '+++++Go Back+++++' and re-start the device by opting 'reboot system now' seen in the recovery menu.

Now, your device (HTC One M7) will take at a few minutes (only for the first time) to complete the booting process.

Head to Settings >> select 'About phone' to confirm the installation of Android 6.0 Marshmallow CyanogenMod [unofficial] CM13 custom ROM.

Downloadble Files:

CyanogenMod [Unofficial] CM13 custom ROM: HERE

Google Apps: HERE

USB Driver: HERE

[Credits: XDA Developer Forum, @dd98]