Retrieve file from iPhone 4s in recovery mode (No backup)

I have an iPhone 4s that was updated without being backed up first and that contains a voice memo file for a school project that is due tomorrow. The update failed, although the cause isn't known. It was over wifi and the wifi signal was strong and consistent. Maybe the actual internet service cut out. I don't know. Now, the phone has been replaced, so it no longer has cell service either. I've been asked to retrieve the file off of it.

I've tried hooking it up with iExplorer and it won't discover in there. I've also thought of jailbreaking it, but I'm not sure if that requires deletion of all the drive contents. I'm also open to breaking the thing open and somehow mounting the drive on another computer, but I'm not sure if there are adapters available for that or how possible it is. Maybe there's a way to restore and then recover the deleted files? Again, I don't know. I'm not typically an Apple user, although I do have access to Windows, Mac, and Linux OS's if need be.