Sunday, August 25, 2013

Updating Nexus 7 (2013) from JWR66N to JSS15Q on Windows

So the Nexus 7 had 2 issues at launch: GPS & Multitouch

The launch android build that comes with the Nexus 7 is JWR66N. The fixes are in JSS15Q.
Find your build number: Settings > About Tablet > Build Number

There was a patch soon after launch, JSS15J, but it doesn't fix either of the above issues. If you don't already have JSS15J google probably wont give it to you over the air (OTA) any more, because it doesn't fix the issues and might make them worse. If you already have JSS15J don't worry, you can still upgrade.

Now if you're squeamish about developer mode you shouldn't be here, just wait for Google to give you JSS15Q over the air. But if you want to get your hands dirty you can resolve those pesky issues now!

1) You'll need developer mode enabled on your tablet.

2) You'll need to change the USB mode on your tablet to "Camera(PTP)".

3) You'll want "stay awake" and "usb debugging" enabled in your developer options on your tablet.

4) You'll need to download and unzip the Android SDK for Windows.

5) Launch the "SDK Manager" in the zip you just downloaded and install the "Google USB Driver". (It'll probably ask to install the SDK and Android 4.3 while you're at it.)

6) Modify the USB driver to add the device ID of the nexus 7 when in recovery mode.

7) Plug in your tablet via USB (it will attempt to install drivers if it's the first time or it has failed before).

8) Install the newly modified device driver.
- Go to the Windows Device Manager, select your tablet from the "Other devices" category, right click and select "Update Driver Software".
- Opt to browse your computer for driver software and point it to "\extras\google\usb_driver".
- Note that the modified driver won't pass checksum and thus wont pass signature validation. So you'll have to approve it when it warns you.

9) Run adb to request device debug authorization.
- Open the command prompt (cmd in the start menu).
- Navigate to \platform-tools
- Run "adb devices"
This should print out one device as unauthorized.

10) On your tablet, authorize your computer. Select "always allow from this computer".

11) Run "adb devices" again to make sure your device says "device" and not "unauthorized".

12) Download the "JWR66N->JSS15Q OTA" or "JSS15J->JSS15Q OTA" depending on which version you have on your tablet (Settings > About Tablet > Build Number).

13) Use adb to reboot your tablet into recovery mode and side load the update.
- Follow Step 11 onward from

14) Do a happy dance!

For the record, I found the responses on this stack overflow question helpful when trying to figure this all out:

Apparently this process is easier on the Mac, because the device drivers don't have to whitelist device IDs and "just work".

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