Michael points out:
Just I've tried by adding "-comspeed 9600" option to rmgr, also
^^^^
"-comspeed 9600" is not an Rmgr option but an option for the Fiasco kernel, like this: (slightly edited from my menu.lst)
I see! Adding the option to the Fiasco kernel, GDB successfully connects to the target PC. Sooner I will check the revised Fiasco.
I was reading the manpage of L4 (telling "-comspeed" as the option for rmgr) and not of Fiasco (telling it as for main). I was wondering why rmgr does not understand options like "-comspeed", "-comport".
l4-hackers@os.inf.tu-dresden.de