Hi, the system.img a backup from Android /system partition is a main part of the android. But this guide we just dump that /system partition, it's the easiest way.
I'll try to help you do that:
1. Is your phone rooted?
If you haven't done that, then use Z4Root(super easy app
) and you can get it from here:
http://www.upload.ee/files/997919/z4root.1.3.0.apk.html
Download that file and copy to sd card and install.
Open that installed app and root your phone
If you need help with that, then there is little how to here:
http://www.worldofnubcraft.com/285/rooting-a-lg-optimus-one-android-phone
2. OK, rooting done, now we need terminal app: You'll find that from Market. Just search "Android Terminal Emulator" it's from Jack Palevich and install that.
3. Now open the Terminal Emulator and enter these commands without "" and hit enter after command, these 3 command should be it:
"su" it asks for a root privileges and you allow that
"cd /system"
"tar zcvf /sdcard/system-dump.tar.gz *" and wait when it finishes. it takes some time. It's done when you see #, it takes couple of minutes max.
4. That file is now on your phone SD card and upload that system-dump.tar.gz file to somewhere and let me know