The following is simply an "FYI" as a possible consideration and/or alternative.
I, too had my original 840 screen crack under very mysterious circumstances and replaced it with a second 840 (not Inkpad 2).
While I was always satisfied with the units' actual readability, I was never enthralled with their oft times quirky software through all versions.
I recently went the Indiegogo route and "invested" in a new Illumina XL HD with a 7.8 inch screen and running (at the outset) Android 4.2. I did this primarily so I could have a $179.00 unit (with shipping $204.00) as part of their kickstarter program that would allow me to use the Prestigio ereader app that I have (and love to pieces) on my smartphone and tablet. At my request, they actually did a brief demo for me showing it would run on the unit! The new unit is scheduled for delivery by the end of September. It does not have an external sd card slot but since I will be using it for my ebook storage only, the internal 16 GB is more than sufficient to my reading needs. BTW, I will be using this as an e reader only and sideloading all of my books from my Calibre libraries.
https://www.indiegogo.com/projects/i...oid-e-reader#/
https://www.youtube.com/watch?v=e28kv-dEaRc
While the 7.8 to 8.0 inch screen size works for me as it closely approximates a "trade paperback" size page, my personal sweet spot is my still functioning Nook HD+ with a truly superb 8.9 inch screen. I long ago rooted it to full Android and it continues to function well. My primary uses for it are for graphic comics and for reviewing/editing photos from my digital camera when on trips. Frankly, if some company had actually come out with a truly non-reflective (not just non-glare) screen protector that I could have used, I would still be going full blast with it. It was/is truly one of the best tablets made in my humble opinion and the unsolvable led screen reflection issue is what stopped my general usage of it.
Hope this helps with your search for a replacement unit!