/etc/init.d/rcS cannot edit on Mini2440

I have to change rcS file on Mini2440 installed qtopia. I want to open
qtopia . I use 

vi /etc/init.d/rcS   
Then  I view all content on command line 

then I type 'i' to change file   
then I remove '#' letter from following lines

#bin/qtopia &                                     
#echo "                                  " > /dev/tty1
#echo "Starting Qtopia, please waiting..." > /dev/tty1 

then I type Esc then :wq    
but there is no effect. Neigther file is saved nor file is closed. 
There is no effect. 

But Before I changed this file . But now , Nothing... 

Is There any idea to change this file. I am confused ...

:wq!   save and quit  Maybe, :wq is OK haven't tried it.

Root filesystem on Nand, SDcard or NFS?

For SDcard do a <sync> before proceeding.

I migth change chown of file. Beforen I could change this file , Mini 2440
has Qtopia , yaffs file system

Are you running Qtopia 2.2 as found on the downloads page?  

I recall having problems changing this file years ago.  I think it has
something to do with /etc being mounted on tmpfs.

Ah, found it . . .

Do you have this in rcS:

*************
echo "*Mounting tmpfs ..."
mkdir /tmp/etc
cp -ad /etc/* /tmp/etc
mount -o bind /tmp/etc /etc
*************

This is done so that when you "mess about" with /etc it will be returned to
it's default behaviour on reboot.

If you want to be able to change rcS and anything else in etc just comment
out all those lines.

Good luck!

edit the file 
do :wq
wait for around 15 sec .. reboot system you will get updated one

"wait for around 15 sec" ????

man sync

what about  ESC and ZZ for saving rcS file.