The K3Flasher utility can have the mx31 support added and that limitation (of the ATK) taken into account.
Freescale has another release of the ATK in the works (to take care of some license issues) - they may also fix this limitation.
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The one you found may be one of those in the set linked to in the first index entry:
https://wiki.mobileread.com/wiki/DX%2...ndex#Teardowns
Which has a few additional detail images in the image gallery.
I will dig around in my browser history, see if I can find the images I had in mind. It was only last week that I was looking at them (a set of 53 detailed images if I recall correctly).
And I obviously forgot to index them once I found them, my bad.