I intend to close this bugreport.

Rational: For one reason live-initramfs is getting redesigned/reimplemented 
those days and I don't want to invest too much further time in the old code. 
For the other reason proper device support works in userspace much better/
reliable than in live-initramfs and adding such a feature could result in 
further complexity.

Is there any bootoption you really could use only with initramfs? Because "grml 
serial" is just an alias for "console=tty1 console=ttyS0,9600n8" and grml2ram 
is "toram=grml.squashfs".

thanks && regards,
-mika-