I did the manipulation on a Nexus 5 (2013) who was on Android 5.1.1 (LMY48B) rooted.
Now my phone have Android 5.1.1 (LMY48I) rooted and I didn’t loose data during the process.
I used Windows but you can do it on linux and Mac OS the same way.

This procedure works for LMY48M too.

Please note that I will not be responsible if you loose data or brick your phone. Please do a backup BEFORE the procedure just in case of.

Download the new android image for your Nexus here

Download the Android SDK, it will provide the tools (adb and fastboot command) we need.

Extract the Android SDK archive
Go on the extracted folder tools/ and launch android.bat (for Windows) or open a terminal on linux and Mac OS and execute in the same folder the commande ./android

Deselect every boxes and select Android SDK Platform-tools
Click on Install 1 package…
Accept the license and launch the install

Extract the Android image of your Nexus (on Windows you can use the program 7-zip to extract the .tgz) (for me it is named hammerhead-lmy48i-factory-a38c3441.tgz)
Open the extracted folder and extract again the zip file (for me it is named image-hammerhead-lmy48i.zip)
Copy the following files in android-sdk-windows\platform-tools (or equivalent for linux and Mac OS) :
– boot.img
– system.img
– recovery.img
– radio-hammerhead-m8974a- (or equivalent depending of your Nexus)

Restart your Nexus in the Bootloader
To do this, power off your Nexus and hold VolUp, VolDown and Power button until you see the bootloader
Or activate the USB debugging and type ./adb reboot bootloader

Now open a terminal (for Windows press WINDOWS + R keys and type cmd)
Go on the android-sdk-windows\platform-tools (or equivalent for linux and Mac OS)
Type the following commands:
fastboot flash radio radio-hammerhead-m8974a-
./fastboot reboot-bootloader
./fastboot flash recovery recovery.img
./fastboot flash boot boot.img
./fastboot flash system system.img

! Keep the terminal open, you will need it after !

Restart your Nexus (use the VolUp/VolDown buttons to select restart in the bootloader and push the Power button to select)

Now you have to download the custom recovery (here I used Clockworkmod but you can use another one, it’s relatively the same procedure)
Download Clockworkmod for your Nexus
Extract the archive and put the .img (here recovery-clockwork- file in the android-sdk-windows\platform-tools (or equivalent for linux and Mac OS)

Download SuperSU (to root your Nexus)
And copy the file on your Nexus

Restart your Nexus on the bootloader again
On the terminal, enter the following:
./fastboot flash recovery recovery-clockwork-
./fastboot reboot-bootloader

Select the Recovery option of the bootloader
You should now see the custom recovery menu

Select install from zip
Select the UPDATE-SuperSU-v2.46.zip file
Install it and reboot your phone (you don’t need to select « Fix root » option)


Based on the article of Aaronhastings.me