i have multiple times my Color 2 because it was buggy as fuck (I bought it on release) and they added a nice fix for an issue.
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I'd open the device to keep reading a book and it would be at some random page and not that page I had closed it at, this seems to have been fixed and it was super annoying going back 100 pages to find where I was at.
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When the device was put down with the cover folded back, you could not start it again without moving the cover aside to get to the power switch, they fixed this by letting to use a page turn button as a power switch if it was switched off, excellent fix for an an annoying problem.