It sounds as though you just need to modify your environment variables to boot from the Meteohub SD card. Those settings aren't very friendly to booting from other cards, but you could probably prepare an SD card the Meteohub way and figure it out if you wanted. The main thing about Meteohub is that it tries,
continually, to boot from SD card. If it fails to find a suitable card, it resets and tries again. It will do this forever. Therefore if / when you swap from Meteohub to another system, ideally, you should take extra care to perform a graceful shutdown.
http://www.newit.co.uk/forum/index.php/topic,238.0.html