@Cex: You're welcome to try to figure out Kobo's eInk kernel driver, I'm still completely puzzled as to whether it's actually trying to ninja-use some regal/reagl updates modes *sometimes* or not
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One thing we did confirm with KOReader is that asking for those *explicitly* does not yield acceptable results (... on a H2O, at least).
The Aura was interesting on that front, because it did things differently, but I've never had an Aura on hand at home (only seen 'em in a shop).