I came across a forum explaining that it "might" be possible to make an image of an iPhone's filesystem using dd. I put "might" in quotes because I doubt the filesystem stays consistent during the time it takes dd to create the image if the phone is running. If this is at least semi-reliable, is it possible to run dd the other way around?

I have an iPhone 3G running iOS 4.2.1 and have no problem connecting this to my laptop running Ubuntu 8.04 and adding/removing pictures, songs, etc. using ifuse, gtkpod, and so forth (Yes, I know, 8.04 is a bit old for this, but I managed to compile everything from source and it all works as it is supposed to).

My main question is, what "device" does ifuse mount, exactly? I'm not seeing anything new under /dev when I plug the phone in (yes, I do have usbmuxd running in the background, which on 8.04 needs to be started manually using sudo. Awkward, but it does work).

I haven't heard of anyone doing this, but is it possible to directly write a dd image to the phone using whatever "device" ifuse uses? If not, what are the implications of mounting the phone using "ifuse --root ~/iPhone" or similar, making a tarball (or image--at least something that keeps track of links and permissions faithfully) of the entire contents of this folder, and restoring it later?

I ask this because I'm considering downgrading iOS and would like to have a verbatim copy to restore from if I'm not satisfied. As far as I know, iTunes just reinstalls whatever was there from scratch and, well, I will just say, that's not good enough, for numerous reasons that I am obliged not to mention. Thanks in advance.

Hi, not sure about dd, however you said "at least bypass ifuse". It sounds as though your iphone has been "jailbroken", if that's right then you can use sshfs to mount the fs. I read that sshfs gives faster transfers than using ifuse.

Thanks for your reply. I presume that you are mean to mount the phone over the network? That may be fine for backing up the phone's file system to an image file, but (over)writing an existing image onto the phone would probably fail, as the contents of the (original) file system are what would be maintaining the network connection on the phone itself.

What I meant by "bypassing ifuse" is, is there a way to write to the phone while it is connected to the computer AND not mounted? Much like inserting a flash drive and unmounting it (without "ejecting" it)? That way you could have something like /dev/xxx to write to.