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Popular custom ROM developer community CyanogenMod has released a new CM12.1 series of Galaxy firmware to Samsung Galaxy S5.

It is around 259MB in size, is based on Android 5.1.1._r24 Lollipop OS and is said to fix the recently discovered security loop-hole, Stagefright. The vulnerability, if left unchecked, might leave Android smartphones prone to data theft by hackers via mp3 audio files.

Read more: Android Stagefright 2.0: Everything you need to know

Things to remember before installing the custom ROM

  • Though installing the custom ROM improves the device's performance and UI experiences, it makes the company warranty void and it 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 forward with custom ROM installation.
  • CyanogenMod [official] CM12.1 series Android 5.1 Lollipop firmware has to be installed on Samsung Galaxy S5 -klte - models only; if tried on other devices, it might get bricked [To check your device model: Go to Settings >> About phone >> model number].
  • Installation of custom ROM requires clearing of memory in the smartphone, so make sure to back the data by installing Clockwork Mod (CWM) Recovery/ TWRP in the smartphone.
  • Make sure to install USB drivers on the PC, or else your phone (Samsung Galaxy S5) will not be recognised by the computer.
  • Make sure the device has more than 80 percent battery, or else there is a chance of the smartphone getting temporarily bricked if the installation process is interrupted mid-way.

[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. International Business Times, India Edition 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.]

CyanogenMod CM12.1 Downloadable files:

New Samsung Galaxy S5 CM12.1 [Snapshot]: HERE [Build date: 07/10/2015]

Cyanogen Recovery: HERE

Google Apps: HERE

Step-by-step installation procedure of CyanogenMod [official] Android 5.1.1 Lollipop CM12.1 Custom ROM on Samsung Galaxy S5 (klte) models:

Step 1: After downloading CyanogenMod CM12.1 [Snapshot] Android 5.1.1 Lollipop custom ROM and Google Apps in the PC, connect Samsung Galaxy S5 to the computer via USB cord.

[Note: Before plugging the phone to the computer, be sure that you have installed the USB driver software, if not, click HERE to download the firmware]

Step 2: Place Android v5.1 Lollipop CM12.1 custom ROM zip file into the phone's SD card memory. [Note: Users are advised to paste the .zip file in SD card root, not in any other folder.]

Step 3: Turn off the device and disconnect from the PC.

Step 4: Perform the regular Recovery Mode sortie by press holding 'Volume (up)', 'Home' and 'Power' buttons.

Step 5: After entering the RECOVERY mode, clear the phone memory, by selecting 'wipe data/factory reset'

[Note: use 'Volume' keys to navigate and 'Power' button to select options, while operating under Recovery Mode]

Step 6: Clear the cache memory by choosing 'wipe cache partition'

Step 7: Return to ClockworkMod recovery menu, and select 'advanced' and tap 'wipe dalvik cache' [Note: This step is optional, but many recommend the procedure so that users will not face boot loops or any other errors in the middle of custom ROM installation]

Step 8: Come back to main recovery screen and then tap 'install zip from SD card'

Step 9: Tap 'choose zip from sdcard' and go to Android 5.1 ROM .zip file in SD card and enter the installation process. Once again, reboot to Recovery mode and then flash Google Apps .zip file [Note: use 'Volume' keys to navigate and 'Power' button to select options]

Step 10: 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 (Samsung Galaxy S5) will take a few minutes to complete the booting process.

Head to Settings >> select About phone to confirm the installation of CyanogenMod [official] Android 5.1.1 Lollipop CM12.1 custom ROM.