AW: Ich habe meins geschrottet!!
The SD-Card already uses this layout, partition 1 is a fat partition that contains:
mca_card.bin, mcaboot.ini etc.
partition 2 contains the apex bootloader.
(With lpc313x you are on the right track the MCA is based on this board)
But you won't be able to simply put a different linux on there,
you'd have to at least get the kernel to boot.
That it didn't boot may be caused by the incorrect commandline,
using this apex I haven't found a way to edit it though (Usually "setenv" or something the like).
Can you please post the output of "printenv".
I'm starting to think it's not the flash which is broken, but the RAM,
in which case there is not much you can do.