Installing Android 5.1 directly on your Nexus 7 2012 Wifi

Introduction

When I first got 5.0.2 pushed to my Nexus 7 I was quite exited - it was different, and (despite remioving my Email client, and such like) I was quite looking forward to it.

But...it crashed. Often.

Locked up...for no reason.

Used battery quickly.

And generally made itself a PITA.

Bad call, Google...

So, in the interests of my sanity, I downgraded back to 4.4 which was at least responsive and stable.

Now, Google have released 5.1 and the word I hear is that it works, just like it should have done.

But...there is always a "but"...when will you get it? Google pushes are a bit trandom, and it can take weeks.

And will it load automatically, or do I have to update to 4.5, 5.0, then 5.1? And how long will I have to spend with 5.0 before 5.1 finaly gets pushed to my device?

So...I found the 5.1 image from Google, and updated manually.

Background

Updating isn't as easy as you might think: there are loads of sites out there explaining it, but none of the ones I found actually worked - they all assumed you had already done somethign without telling you what it was.

So this time, I made notes in my day-book as I went to give me a chance to repeat it...

Installing

First, configure your Nexus to Camera mode (rather than Media Device):
Settings --> Storage --> Top Left Option (Computer USB Connection) tap--> choose Camera (PTP)

Download your Android image

5.1 Nexus7 2012 WiFi):
google.com: nakasi-lmy47d-factory-bc93dab8.tgz[^]

Open the file with WinZip - it will say that there is only one file, do you want to open that? Say yes. (The TGZ file contains a TAR file, which contains the ZIP you want, with a couple of PC support files.) Unzip all files to a clean folder.

Download ADB and FASTBOOT

xda-developers.com[^]

Copy these files to image folder (I found them under "C:\Users\Griff\adb", but you may need to look elsewhere if you selected "install for all users" - Gawd knows where it stuck them, I still haven't found 'em...

ADB.EXE
ADBWINAPI.DLL
ADMWINUSBAPI.DLL
FASTBOOT.EXE

You should now have 9 files in the image folder.

Download and install the Universal ADB Driver

Google[^]

Enable USB debugging

Settings-->AboutTablet, then tap the build number 7 times (enable Developer mode)

Settings-->Developer Options-->USB debugging

Check it's working

Open a command prompt, and move to the image folder.

Connect your Nexus to the PC via USB.
BACK THE DAMN THING UP!
You are about to factory reset, so you will lose all data in the next step.

Type "adb devices" and press ENTER.
You should see your Nexus listed - if it says "unknown" then tick the "allow debugging from this computer" box on your nexus and do it again. You should get a Hex GUID key and "device".

Take a deep breath, and let's erase your machine...

Type "adb reboot bootloader" and press ENTER

When the Nexus finishes, it'll show an android on it's back, with it's tummy open.

Type "fastboot oem unlock" and press ENTER
This will take a little time.

Back to the PC:
Type "flash-all" and press ENTER
 
Leave the nexus plugged in until this all completes (it will take minutes, not seconds)
Wait for something like:

rebooting...

finished. total time: 155.357s
Press any key to exit...

Press the ANY key! :laugh:

Android will boot.
You should now be able to use the new "Tap N Go" to restore your apps and such like, if you have a second device. If not, start entering your Gogole+ id...  

Points of Interest

Why do some people ignore the Media Device / Camera selection?

Why do some ignore USB debugging?

Why do some ignore unlocking?

History

First version 2014-Mar-13