Dear eager N9 developers!
We know that you are interested in updating your devices to PR1.2 as fast as possible, but we propose that you restrain yourselves to the fully productized and verified updating procedure.
The availability of the update is based on the variant of the Harmattan operating system on your device, and not the current operator or your physical location. See Harmattan version numbers explained (23-Jan-2012) for further details.
The over the air updates are rolled out on a per-variant basis. Some variants are released earlier, and others obviously later. The exact schedule depends on various aspects, including but not limited to variant volumes, time zones and e.g. network owner approval. Please have patience waiting for the update notification to appear on your device.
We recommend that you do not apply your skills or other voodoo in forcing the update from the terminal application. While manually tweaking the settings and trying to force the update may seem to work, you may also end up bricking your device or otherwise rendering the platform or applications to an unexpected state.
A variant release consists of packages that have dependencies to each other. Different variants have different packages and different dependencies. Additionally, apt-get is a component of full software delivery stack and using it directly is not advised. If a user e.g. forces an update of a variant on top of another variant by manually tweaking repository information, this may result in some packages not getting updated, and some being otherwise wrong.
To update your device, only use the over the air updates with device graphical user interface or the Nokia Software Updater.
Remember that great powers come with great responsibility: the warning of potentially losing your warranty when enabling developer mode is there for a reason. The terminal enables you to do plenty of impressive things, but it also enables you to mess up your device's configuration and contents in a spectacular fashion.
In addition, some users have experienced sluggishness on first boot after the update. That is to be expected and is a sign of ongoing cleanup and re-indexing. It should be fairly fast, only a minute or so for most users. However, the duration is dependent on the amount of data stored on the device, and thus the sequence may take significantly longer as well.