Default If you have a working phone you might want to backup all your partitions

Sneakyghost in the General M8 forum wrote a script to "image" all your partitions.

I ran it on mine before updating anything. I forget if it needs S-OFF, Root etc. What ever is required for ADB.

http://forum.xda-developers.com/show....php?t=2696826

I would not share your backed partitions though, these would only for the specific phone you imaged. There is a lot of phone specific information in many of the partitions.
Samsung Galaxy S5 with R.O.D.T