C-118 Hello World micro-howto:
YOU ARE UPLOADING INTO RAM. NO RISK BRICKING ANYTHING (who said "no fun"?!)
Assuming you built osmocom-bb WHEREVER
1. Phone off, battery out.
2. Run:
cd $(WHEREVER)/osmocom-bb/src/host/osmocon
LD_PRELOAD=/usr/local/lib/libosmocore.so.6.0.0 ./osmocon -p /dev/ttyUSB0 -m c123xor ../../target/firmware/board/compal_e88/hello_world.compalram.bin
3. Put battery in and shortly click the red button. Should upload and jump into that gnarley HW.
TODO
See http://bb.osmocom.org/trac/wiki/Hardware/CP210xTutorial (higher baudrates are desired)