Marc, did you encounter this problem in recent grml versions? The bugreport is 
>=1 year old and there have been some changes and improvements in boot related 
code. I never ran into this issue on my own, using usb pens on regular base 
(also with grml2ram). Marking this bugreport with "needs-progress", if I don't 
have any feedback within the next 4 weeks I'll consider closing this bugreport.

Thanks!

regards,
-mika-