Can't the same be said for when law enforcement takes images of hard drives? That happens all the time. There are procedures for maintaining chain of custody that are required to verify these things.
Hard drives have a universal interface for reading out their contents without modification. Most jurors would understand that. Many jurors would equate drastically modifying a device as tampering. Chain of custody doesn't matter. What a juror thinks is what matters.
I wouldn't expect there's much of a difference in how laymen (jurors) understand reading out and using an image of a hard drive and reading out and using an image of a flash device.
First of all, for most of them, it's black magic. For the few who know a bit more, will be convinced by arguments of analogy (after all, nowadays many hard drives are in fact flash devices, and the details of interface protocol are beyond what jurors will care about).
