Calypso firmware update (work in progress), fix for #666 '3G-SIM not recognized'

Werner Almesberger werner at
Wed Nov 19 03:47:27 CET 2008

Bo?tjan Jerko wrote:
> It seems that GSM modem doesn't start.

So you don't even get the

AT-Command Interpreter ready

when doing something like this ?

# stty -F /dev/ttySAC0 115200 crtscts -echo
# dd if=/dev/ttySAC0 bs=1 &
# echo 1 >/sys/bus/platform/devices/neo1973-pm-gsm.0/power_on

> I also tried to use echo -ne "AT\r" > /dev/ttySAC0 command to get some  
> response from GSM modem, but I don't get any.

Flow control is a bit tricky when it comes to sending things to the
modem. I found that our "standard procedure" with cu etc. sometimes
hangs as well. And things actually get worse if I break this down
into basic operations.

That may take a bit to figure out. Meanwhile, the best work-around
seems to be to just try a number of times.

- Werner

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