The CyanogenMod team has recently started launching CM 11 nightly builds for the HTC One, and if you're not willing to wait for the official Android 4.4 release on the device, then CM 11 is one of your best options to experience the OS ahead of time.

This guide will allow you to install the CM 11 custom ROM on the T-Mobile HTC One. Keep in mind that the ROM is still under development, and new "nightly" builds will continue to be released until an RC or Stable version comes out. Bug fixes are constantly on their way. You should also remember that CM 11 is based on Android 4.4, and it comes with the KitKat user interface and extra features. As such, once you flash the ROM, you won't have access to the Sense user interface.

IMPORTANT – READ BEFORE PROCEEDING:

  • This is a guide that works only with the HTC One at T-Mobile. Attempting to apply this ROM on any other smartphone or One variant can result in phone bricking / damaging
  • To apply this ROM, you need a rooted T-Mobile HTC One, running the most recent version of CWM or TWRP custom recovery
  • The flashing process requires you to factory reset your handset. You should backup any important data before proceeding
  • Using applications such as "Helium", "SMS Backup & Restore" and "APN Settings Backup & Restore", you can backup app data, text messages and APN Internet settings
  • You can backup your contacts by syncing them with your Google account
  • Instructions on how to create a NANDROID backup of your ROM are provided below
  • You'll need to connect your device to a computer via USB. Enable USB Debugging before doing so. Go to "Settings" > "About" > "Software information" > "More" and tap the "Build number" several times, until the "Developer options" menu becomes visible. Go back to "Settings" > "Developer options" and then mark the "USB Debugging" check box
  • Your smartphone should have enough battery to remain powered on during the installation process. Make sure the levels are at least at 70%
  • This guide is aimed at advanced users, as it includes unofficial operations. Proceed at your own risk!

HTC One T-Mobile – Install Android 4.4 CM 11 Custom ROM via CWM Recovery:

  1. On your PC's Internet browser, visit this link and download the most recent CM 11 release
  2. Visit this link too, and download the Android 4.4 Google apps zip file
  3. Connect your T-Mobile HTC One to your computer using the USB cable
  4. Copy the downloaded files onto your phone's storage, and disconnect it once the transfer is complete
  5. Reboot the device in bootloader mode. To do so, press and hold the "Volume down" button, and after a few seconds, press and hold the "Power" button. Keep pressing these keys until the screen turns black, at which point release the "Power" key. Release the "Volume" key when in the bootloader menu
  6. Use the volume rocker to highlight "Recovery" and select the option by pressing "Power"
  7. Now, create a NANDROID backup of your ROM, by selecting "backup & restore" from the CWM recovery menu and following any additional self-explanatory steps
  8. Once you've created the backup file, return to the CWM screen and select "wipe data factory reset" and "wipe cache partition". From the "Advanced" menu, select "wipe dalvik cache" as well
  9. Go back to the main recovery screen and select "Install zip from SD card"
  10. Browse for and load the CM 11 file
  11. Select "Install zip from SD card" again, and load the Google apps zip file
  12. Select "+++Go Back+++" and then "Reboot system now"

NOTE: When you first reboot your smartphone after a fresh ROM installation, the process will take longer than usual. However, if the phone does not reboot in 10 minutes, or if it's stuck in a boot loop, then you'll need to redo the guide from the beginning while making sure you haven't missed any steps

NOTE: you can return to your previous ROM using the NANDROID backup. Simply reboot in CWM recovery, select "backup & restore" and select the backup file

HTC One T-Mobile – Install Android 4.4 CM 11 Custom ROM via TWRP Recovery:

  1. On your computer, visit this link to download the latest CM 11 file
  2. Visit this link to get the Android 4.4 Gapps package
  3. Use the USB cable to connect your handset to your computer
  4. Copy the downloaded files onto your phone's storage, and disconnect your device once the transfer is complete
  5. Now, access the bootloader menu. Press and hold "Volume Down" for several seconds, and then press and hold "Power". When the screen goes black, release the "Power" key, and once in the bootloader menu, release the "volume" button as well
  6. In the bootloader menu, highlight "Recovery" by pressing the "Volume" keys, and confirm the selection by pressing "Power"
  7. Once in TWRP recovery, create a NANDROID backup. Tap "Backup", mark the type of data that you want to save, assign a name to the file and swipe the "Swipe to backup" button
  8. From the TWRP screen factory reset your device. Select "wipe cache" as well as "dalvik cache" from the "Advanced" menu, and complete the operation by swiping the "Swipe to wipe" button
  9. With the device fully wiped, tap "Install" and load the CM 11 file
  10. Tap "Install" once more, and flash the Google app zip as well
  11. Return to the main TWRP menu, and then tap "Reboot"

NOTE: When you first reboot your smartphone after installing a fresh ROM, you will notice that the process takes longer than usual. That's OK, but if the phone does not restart in 10 minutes, or if the handset keeps crashing, then the ROM has not been applied successfully. Try redoing the guide and make sure the phone is properly factory reset, and that you haven't missed any steps

NOTE: You can return to your previous ROM with the help of the NANDROID backup. Reboot your phone in TWRP recovery, tap "Restore" and load the appropriate file

› See More: HTC One T-Mobile: Install Android 4.4 CM 11 Custom ROM via CWM or TWRP Recovery