[PROBLEM] Boot loop - init process... - loading...

[IriDium]

What next!!!

Always before upgrading or altering anything - make a backup. Xbian gives you the tools, so you can recover, also many OS allow you to read and then write the SD card to an img file.

Or better still, upgrade on a "new" SD card and see if it works - for the sake of £2 for a 2G SD card it has to be worth it

I'm guessing here, but if you hold down the <shift> key during boot, it should bring you too a rescue shell. From there, either use btrfs tools to recover from a snapshot (No I don't know the commands - never needed to)

Or possibly, remove "staging" from sources, and upgrade. It might :-) revert the changes.