I’ve got a Galaxy Nexus phone bought here in Denmark, which I updated to Jelly Bean 4.1.1 using Google’s factory images before it was sent OTA to my phone. I used the fantastic Galaxy Nexus Toolkit to install the 4.1.1 version, unlock and root my phone.
In order to update your phone with the toolkit all you need to know is the model of your Galaxy Nexus. I found a neat trick is to go to the settings of the Maps app, there you will see if your phone is (Maguro, toro or toroplus). On top of the phone model there is also the build which can be either: takju, yakju, mysid, mysidspr. The build can be found in Settings->About Phone.
With that information the toolkit can handle everything else for you including downloading the factory image of your choice.
I’ve been happy with my 4.1.1 but now I get a popup that promps me to update over the air and I must have made a mistake during the initial installation because that update does not work for me. I simply get a “invalid signature” error when I try installing it. So as luck would have it Android 4.2 is now out so I’m installing that. This time I’ll try installing the image manually because I am unable to get my hands on the newest version of the Toolkit.
That turned out to be very simple because I have a maguro and there is a 4.2 takju build on the Nexus Factory Image page. Not only does the file you download from there contain a factory image and everything else you’d need, it has a bat file for installing all of it automatically. Neat!
I’m doing a full backup of my phone now, including using the nice “SMS Backup+” app to backup my messages. After that I’ll be running that batfile and crossing my fingers.
Had some trouble with getting fastboot to recognize my device, but it turned out that Windows 8 had not installed my drivers correctly, after updating the drivers from the Android SDK and installing them for my device everything worked just fine.
One thing to note about this type of update. It is deleting EVERYTHING on my device.
Success! Now running Android 4.2! I just have to let google download all my apps again and setup accounts and I’m back in business.