I wonder if any one had experience of dd an image from 3GS and performed successful recovery.

I use ssh root@iphone-ip dd if=/dev/rdisk0s2s1 bs=4096KB | dd of=iphone.img in order to capture the data partition. After that when I try to scan in Datarescue, I could see all existing picture files but none of them can be opened. I am not able to see any lost picture files.
I tried with 3 or 4 different 3GS with the same result.

I then tried to use "cat /dev/rdisk0s2s1" and then nc across the network with the same result.

I also realize whenever I tried to do dd if=if=/dev/rdisk0 (ie to capture the whole disk image), it will bomb out around 780 MB.

If I do this for 3G, I could get perfect result and even recover any deleted data.

4GS also had the same issue.

Did I miss something ? I jailbreak the phone using jailbreakme.com.

I have been searching for the net for many weeks now trying to get to the bottom of this.