The update is currently pushed OTA (over the air), in stages
It appears that Samsung and Google have finally started to bring the Android 4.2 update to more yakju Galaxy Nexus devices.We reported about a week ago on the availability of the upgrade in a few countries, including Australia and the UK. However, not many yakju Galaxy Nexus owners received it yet.
Well, it looks like Google has already released the Android 4.2 factory image for yakju Galaxy Nexus, which can be downloaded here.
Android users that own a yakju Galaxy Nexus can now manually download the JOP40C update here and install it via ADB sideload or they can wait for the OTA (over the air) update to arrive on their smartphones.
MobileSyrup also reports users have been able to successfully change their device's lineage from yakjuux, the Canadian carrier-bounded Galaxy Nexus, to yakju, though we do not recommend this unless you know what you're doing.