Is there a problem with this app not being able to restore /system?
My experience with this....
Safestrap would get errors restoring /system so I stopped using it.
Bootstrap worked great until I flashed 173 then I started getting /system restore errors again.
I did a fastboot on phone and upgraded to 748 and made a backup. Restored and /system restore worked great.
Upgraded to 173 and once again /system restores would fail.
I tried 3 more times and each time, 748 would restore fine and fail on 173.
Now I just do an advance restore and restore them manually. System still fails but it seems to still flash all of system.