Can't echo to router /dev/ttyS0 after reload/quit!

I have this shell script, that runs:
1. write erase
2. reload
3. answers "no" for the configuration dialog question
4. enable
5 some more commands..

All the writings to the router are echo $1 > /dev/ttyS0.
After step 3, the script commands no longer reach the router!
I have to enter minicom, press Enter, and quit minicom (without "quit"
command. only CTRL-A-q).
It seems as if i enter minicom, type "quit" (and get the "press return
to get started" print), and exit minicom without hitting enter, I
encounter the same problem.
btw, echo-ing "enters" doesn't do the job either.

Does anyone have a clue?!

i'm using a cisco 26xx with ios 12.2.