Copy an iPhone's disk contents (filesystem) to a computer I like to get a clear view at how an iPhone's file system. Especially in the case of damaged data.

Apart from using a professional (and costly) data recovery service, what other ways do exist to transfer (dump) the disk data from an iPhone to a computer.

In particular, what options are there when the disk data is damaged to the point that it can't boot iOS any more, i.e. when the iPhone is in recovery mode but can not reboot, even with a tool such as iRecovery).

I am not looking into breaking into someone else's data here. Assume that I know the iPhone locking password (I understand that this user-settable code is not the actual encryption key, but I hope that there is a way to get to the key when knowing the password).

I am quite proficient with low level disk formats (partitions, HFS, etc.), for instance, I've written a disk editor (iBored), that's why I like to look at what's actually stored on the disk.
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.