Update Nexus 4 to Android 5.1 Lollipop using AOSP Custom ROM Eagleeyetom, the recognized XDA developer, has launched the Android 5.1 based AOSP for Nexus 4 model. However, Google hasn’t given an official update regarding the same as this AOSP ROM can be used in Android 5.0.1 as well. As per the reports given by forum members, the ROM works absolutely in a user friendly manner. Pre-requisites: The following guidelines are made for the Nexus 4 only. Make sure that your device has at least 80% battery backup while doing this process. Create an exact custom recovery tool like CWM or TWRP on your device. Install required USB drivers on your PC and USB Debugging Mode on your Smartphone. Steps to Update Nexus 4 to Android 5.1 Lollipop using AOSP Custom ROM: Step 1: Download the AOSP Lollipop firmware on your PC. Step 2: Don’t unzip any of the downloaded files. Step 3: Download Gapps files in your PC now. Save it without unzipping. Step 4: By using a USB cord, transfer all the above downloaded files to the internal storage of your device from the PC. Step 5: Remove the USB cable now. Switch off your device and reboot it using the recovery mode. Step 6: Move further with the clearing of cache which includes wipe data factory reset, wipe cache partition and wipe dalvik cache. Step 7: Click on install zip from SD card by going back to the recovery mode, and then select choose zip from SD card. Step 8: Select Android 5.1 update. Flash it directly on your Nexus 4 Smartphone. Step 9: Follow the above mentioned steps for the set up Gapps files as well. Step 10: When you’re done with it, then click on reboot system now. Now, you can start using your Nexus 4 running on Android 5.1 Lollipop AOSP custom ROM firmware.