We have just purchased a set of Raspberry Pi 2 boards to upgrade our Raspberry Pi B+ / HDMIPI set-up which we have been using for Computer Science this year. I will not go into the reasons why or the specifications of the Raspberry Pi 2; but needless to say the performance increase seen will make teaching with these devices much easier!
So we received our new Pi 2 boards and got straight into removing the old B+ boards from our HDMIPI set-up and installing the new Pi 2 boards. Pretty soon I ran into an issue though; having replaced the Pi board and using one of our SD Cards with our current image installed on it, the system would not boot; it just sat there at the rainbow boot screen. It turns out that the Pi 2 has an updated ARM processor and therefore needs the latest updates installing for the Pi to boot. Now I could have just downloaded the latest Rasbian image and been up and running, but we have quite a few customisations to our image which I wanted to keep