I already did some pics, but can't post it here, due being a new member.
The unit boots into RCM, but I'm not sure a full dump is possible, as hekate reports a size of 29GB instead of the (probably) expected 54GB.
Well you can upgrade or downgrade the unit easily (I imagine) since each revision only checks for 1 burnt fuse. So I guess that could be handy, although I imagine there is much more potential for this unit in the hands of those who know wtf they are doing. (unlike me)
How would the seller have gotten the unit themselves, were these only handed to developers or would they have been used as floor models in stores?
Given that OP said the cart slot won't work, I'm assuming that just means retail carts don't run, but maybe demo or dev carts would work in it (if those are even a thing for the switch).
Like how 4.0.0 firmware updates the card slot on retail units, maybe the edev firmware makes the card slot only work with special cartridges (to stop shady devs trying to sell them on or use them personally afterwards).