1000 Thanks to Edmund!
I think someone said that "-nopentium" has no effect on a 486.
OK, I will check l4-hackers archive.
Confusingly, the word "Pentium" appears on the console in any case, whatever you do.
Yes, "-nopentium" option does not stop to show the word "Pentium".
However, when I boot without "-nopentium" on 486 PC, the situation becomes worse: the system stops before starting L4-Linux /or hello server.
Just I've tried by adding "-comspeed 9600" option to rmgr, also "set remotebaud 9600" to .gdbinit. But the result is just same.