I would love to help you with that, I think that the best way to do this is making a backup in a drive, some users have used these methods:
There isn't an official program to do this, but this threads can you help with your goal.
I hope you find this helpful.
Yes, that appears to have worked, and is good for my purposes.
I still would like to have been able to take an image by way of dfu-util, but I can live with this. I see dfu-util has an option for reading back an image, and I attempted to use it, but it just threw an error with no indication of what it was. I tried the following (to do the rootfs):
dfu-util -U C:\Users\Bill\Desktop\image -d 8087:0a99 -a 7 -v
and here is what I got back:
Opening DFU capable USB device...
Run-time device DFU version 0110
Claiming USB DFU Interface...
Setting Alternate Setting #7 ...
Determining device status: state = dfuIDLE, status = 0
DFU mode device DFU version 0110
Device returned transfer size 4096
Copying data from DFU device to PC
Upload [ ] 0% 0 bytes
Received a total of 0 bytes
It is good to know that it was useful, about the dfu-utils method I have not heard about that, and as far as I know that method is not validated on the Edison.
Personally, I recommend you to use the provided method.
Have a nice day.