Hello Jochen
I did some contract work for Megatel computers a few months ago -- they
make SBC's and wanted to get Linux running on them since some of their
customers had inquired about the possibility. Anyway their boards use
flash memory from M-Systems with the TrueFFS. Like you I booted DOS and
then loaded a linux kernel from the flash -- I inquired about obtaining
information about how to write a device driver for the flash but was
told that it would be difficult since M-systems doesn't want to release
that information so I didn't pursue it any further. Anyway unless M-systems
changes it's position I don't think it's possible unless you want to try
some reverse engineering.
Regards
Emil