serial console on Pi Zero W

[Pouya Tafti <pouya+lists.netbsd%nohup.io@localhost>]

Hi,

I'm trying to get the serial console to work on a Pi Zero W
running the latest -current image, and probably missing
something obvious.  I've hooked up the Pi to my laptop via
a cp2102 USB-to-UART bridge. The wiki seems to suggest that
all that is needed for the serial console to work is to
remove console=fb from cmdline.txt on the boot partition
(UART is already enabled in config.txt via enable_uart=1). 
But I don't see any output when I connect to the Pi with cu
on my laptop:  

# cu -s 115200 -f -l ttyU0
Connected

and nothing afterwards.  With the fb console enabled and an
HDMI display I can see that the Pi boots normally. 

Would appreciate any suggestions.

Many thanks,
Pouya