Hm, I now tried EVERYTHING I could. Removing SD Cards while booting, removing them while writing to them, reinserting them, etc.
Nothing.
The only thing that happens is that they get a new mountpoint (as they are not cleanly unmounted) but I didn't manage to corrupt them.
Would be really great if we could narrow that down, as I can't find any way to corrupt my card... and I've been using it for four months on my prototype yet.
Regarding mountpoints:
/media/mmcblk0p1 = The main SD Card, partition 1.
/media/mmcblk1p1 = Second SD Card, partition 1.
/media/mmcblk0p2 = The main SD Card, partition 2.
etc.
Now if you remove a card and put it back in, it usually goes to /media/mmcblk2p1, as /media/mmcblk0p1 isn't properly unmounted (and therefore might show you some crap if you browse there).
Your card shouldn't be affected by this.
We are working on that increasing mountpoints, but it's not easy in Linux
