HP41CL newbie question

[Neve]

This is what I get:

java -jar clupdate-1.1.0.jar --update rom_files_171202.zip /dev/tty.usbserial 4800

04:36:46 --update [fileName: rom_files_171202.zip] [portName: /dev/tty.usbserial] [baudRate: 4800]
04:36:46 File rom_files_171202.zip loading ... done
04:36:48 Serial /dev/tty.usbserial opened at 4800 baud.
04:36:48 Waiting for 41CL commands ...
04:36:50 Received OPEN_CHANNEL_REQUEST(0x41)
04:36:50 Sent OPEN_CHANNEL_RESPONSE(0x42)

After CMOPEN, nothing on the calculator. Zilch.
It just returns to 0.0000

What am I missing...?