OK if you have used 2.1 you noticed remount commands doesn't work, I have fixed that here is the code copy and paste below code into a text editor save as remount, no extension.
copy to your sdcard via usb to computer.
Code:
#!/system/bin/sh
#
# Remount /system rw/ro
case "$1" in
ro)
echo "Setting /system to ro"
mount -t rfs -o remount,ro /dev/stl5 /system
;;
rw)
echo "Setting /system to rw"
mount -t rfs -o remount,rw /dev/stl5 /system
;;
*)
exit 1
esac
Now you need to unmount your computer.
Code:
open terminal
su
mount -t rfs -o remount,rw /dev/stl5 /system
cat /sdcard/remount > /system/bin/remount
chmod 4755 /system/bin/remount
to test that it's working.
in terminal
Code:
remount ro
mkdir /system/bin/test
remount rw
mkdir /system/bin/test
rmdir /system/bin/test
remount ro
reboot
after reboot you can repeat above test if you like.