Read only file system on Android
Not all phones and versions of android have things mounted the same.
Limiting options when remounting would be best.
Simply remount as rw (Read/Write):
# mount -o rw,remount /system
Once you are done making changes, remount to ro (read-only):
# mount -o ro,remount /system
works for me and seems to be the simplest solution.
Got this off an Android forum where I asked the same question. Hope this helps somebody else.
On a terminal emulator on the phone:
mount -o rw,remount -t yaffs2 /dev/block/mtdblock3 /system
Then on the cmd prompt, do the