If you've upgraded to Android 5.0 Lollipop but are unsatisfied or encountering unwanted issues, reverting to Android 4.4.4 Kitkat is necessary. Here's how to downgrade from Android 5.0 to Android 4.4 on Nexus devices:
Step 1: Download the desired version for downgrading. We provide a link here for you to choose suitable versions from Google Develop.
Step 2: Download ADB Tools.
Step 3: Activate USB Debugging mode. If you're unsure how to do this, refer to How to Enable USB Debugging Mode on Android.
Step 4: Back up your device data.
Step 5: Turn off your device.
Step 6: Press and hold Power and Volume Down buttons to enter Fastboot mode. In Recovery Mode, you can use the volume buttons to select Recovery Mode and press the Power button to confirm.
Step 7: Select the old Android version you downloaded earlier by moving the volume button and selecting with the Power button.
Step 8: Scroll down to 'wipe cache partition' and press Power to confirm.
Step 9: Scroll down and select wipe date/factory reset and press Power to confirm.
Step 10: Connect Nexus to your computer via USB.
Step 11: Open the ADB Tools folder and find the flash-all.bat file, then double-click it. Wait for the process to complete, and your device will restart, successfully reverting back to Android Kitkat.
So we've guided you on downgrading from Android 5.0 to Android 4.4 on Nexus devices. The release of Android 5.0 is indeed a great joy, but for many reasons, we want to go back to Kitkat.
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