Copy an iPhone's disk contents (filesystem) to a computer
One way to copy the data is to jailbreak the iOS device, then using a terminal program on the device or log in via ssh from a remote computer, then copy the data with the dd command, as explained here. But that only works if


The iOS is bootable and
The iOS can be jailbroken.


So, this is not the answer I am looking for but it's still an option that fits the above question, somewhat.