So, you will need YOUR WORKING phone, root and terminal emulator ;)
For backup open emulator and write:
su
(your phone will ask you for root acces)
dd if=dev/block/mmcblk0p3 of=removable/MicroSD/mmcblk0p3.img
dd if=dev/block/mmcblk0p5 of=removable/MicroSD/mmcblk0p5.img
(MicroSD is name of my...