Do you own a Nexus 7 2012 or 2013 edition? Did you take the plunge from Kit Kat to Lollipop and find the experience surprisingly underwhelming? Did your tablet thank you by becoming a useless, sluggish mess? Well if your nodding your head, then you’ll either be happy or sad to discovered your not alone. For Christmas 2013, I bought my girlfriend a new Nexus 7 (2012 edition), which she was excited about having. She hadn’t been expecting a tablet, but in the months that followed she found more then a few uses for it. From reading comics, browsing Pinterest and storing cooking recipes. The Nexus 7 was lightening fast compared to her mobile, combined with the large screen it meant her laptop hardly got used. But this wonderful friendship was sadly going to end abruptly one evening, when the tablet informed her there was a system update available. The update in question was for Android 5.0 also known as Lollipop. Trusting Google, she allowed the tablet to update and in the days that follow slowly came to regret the decision. Her once nippy Nexus 7 was performing as well as a three legged, blind horse in the grand national.
When things break, I’m usually the one my family and friends go to for tech support. Just because I know how to turn on a multimeter, they seem to think I know what I’m doing, those crazy fools! lol
A quick look at the lethargic tablet had me wondering if the cache needed cleaning out. In recent years Android has improved a lot, but anyone who remembers cheap Android 2.2 tablets from China. Will recalled the monthly cache wipes required to keep the system usable. Looking online I found other people had the same idea, but with mixed success. Almost all the articles & posts that I read were adamant that the upgrade was breaking their tablets. Slowing down the performance, causing reboots and random force closes. As one might expect, after wiping the cache, things didn’t improve much. The tablet stabilised slightly, but continued to reboot at random times and perform terribly. The conclusion? the Nexus 7 needed rolling back to KitKat. While it was a software downgrade, it would be a performance upgrade. After putting the rollback off for 6 months in the hope Google would sort out the problem and release a bug fix. One has sadly not been forth coming and it seems like Google have move on and abandoned the Nexus 7 community. As a techie I can tell you that computer hardware has a short shelf life, products are superseded in a very short space of time. But even with that in mind, users of the 2013 Nexus 7 were not spared from the slow down problems that came from the 2014 Lollipop update.
Many users have rolled back their tablets to 4.4 (KitKat) and reported it restores the devices performance and battery life. So as it seems we’re left to fend for ourselves, I decided to bite the bullet and perform the hairy task of downgrading the tablet. I’m not usually prone to feeling nervous when working on hardware, but when its not my own, I become more aware of the risk I’m taking in fiddling. You can following instructions to the letter and still ended up with a bricked tablet. And sometimes means replacing the main board just resuscitate it!
The guide I found useful was this one, written by Kris Carlon.
The guide is pretty straight forward, however one of the steps did trip me up. So while your here at BMV, I’ll walk you through what I did.
(Warning this guide could brick your device if not followed properly. It is intended for intermediate users, with some knowledge of the command prompt. If your not familiar with flashing devices, ByteMyVdu HIGHLY recommends seeking out a nerd or a friend who looks as if they know what they’re doing. If things go wibbly wobbly, it’s not my fault!)
You may need to install “7-Zip” so that your computer can unpack the files in guide below.
The first thing we are going to need is a restore image, thankfully Google offer these on their website for anyone to download. Now pay attention for this part, you need to download the file specific to your device. A Nexus 7 (2012) image will probably brick a later 2013 model or at the very least disable its onboard camera. The list is fairly straight forward, as I was flashing a 2012 edition, I scrolled down to “`nakasi’ for Nexus 7 (Wi-Fi)” and selected the last release of Kitkat (4.4.4).
If you have 2013 model scroll further up the page and choose the file for suitable for your device, Wi-Fi or Mobile.
Assuming you have successfully downloaded the image file to your computer, we will begin the process of preparing your tablet for the rollback.
You will need some software to enable your computer to communicate with the tablet. So download the ADB tools from:
Once it is downloaded unpack the archive to your hard drive. I find the easiest place is the root of “C:”. So you should now have a folder called “adb tools”, lets locate the factory image you downloaded earlier and unpack it to the “adb tools” folder you just created.
If you look inside the “adb-tools” folder you should find a single file with the extension *.tar, this is another archive, so use 7-Zip to unpack it to the current directory (see fig.1)
Assuming your device is switched on, we need to make sure USB Debugging is enabled. You can do this by going in to the settings of your tablet ‘Settings > Developers Options’. Make sure USB Debugging is enabled. If you don’t have Developers Options listed in your settings menu, you will need to enable it. This is pretty easy to do, simply go to ‘About Phone’ and tap the ‘Build Number’ repeatedly until a notification appears.
Unless you have already done so, you will need to unlock the bootloader of your tablet so that it will accept the update. First turn off your Nexus 7. Then Press and hold the Volume Down and Power button to enter the Fastboot menu (fig 1.2). Connect your tablet to your computer via a USB cable.
Now open a Command Prompt via the Start Menu, clicking Run and entering ‘CMD’. Navigate to the ‘adb-tools’ folder on your hard drive, you need to be in the directory that has the ‘adb.exe’ and ‘fastboot.exe’ files. From within this directory, execute the following command to unlock the bootloader.
fastboot oem unlock
Press the Volume Up button to accept the command and press the Power button to confirm. The bootloader will now be unlocked.
Now as I already warned you, if you haven’t made a backup of your data, do so now as it is your last chance. If your all set and ready to go, then let us proceed.
Turn off your Nexus tablet, then press and hold the Volume Down button and the Power button to enter fastboot mode. You should once again see the Android laid on its back (fig.1.2).
This is the part of the original guide I tripped up on, as it instructs you to press the Volume Up button and enter Recovery Mode. This did not work for me, perhaps because my tablet is using the stock recovery. While still on the fastboot screen (fig 1.2). Connect your Nexus tablet to your computer using your USB cable.
Now on your computer, navigate to the ‘adb-tools’ folder, find the unpacked folder containing the factory image you downloaded. You should see a file called ‘flash-all.bat’ inside the folder (fig 1.3). These files need to be in the same directory as the ‘adb.exe’ and ‘fastboot.exe’, otherwise they will not run properly. So copy and paste them into the same directory (fig 1.4)
With that done, double click the file ‘flash-all.bat’, your computer will now proceed to flash KitKat to your tablet. DO NOT touch your computer or tablet while this is happening as it may brick your tablet.
When the process is over, your tablet should reboot and begin loading Kitkat. Go through the setup and restore your files and enjoy a snappier tablet!
Until next time, keep on geeking!