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
adb remount
works for me and seems to be the simplest solution.