I just newcomer in osmocombb so I guess still miss various concept here. I tried to clarify (several question mark below) the stuff which I hope don't bore anyone here :).
1). sylvain branch: yes. I am using sylvain test branch and uncomment the TX part as written in SIM Reader wiki for firmware Makefile.
2).
osmocon
This is the utility to upload osmocombb firmware from laptop to my motorola c118 through usb cable.
and here's the output I got,
$ ./osmocon -p /dev/tty.usbserial -m c123xor ../../target/firmware/board/compal_e88/loader.compalram.bin