Allwinner F1E200 based ebook readers

• I found several of these generic e-book readers on eBay: https://www.ebay.de/itm/E-Book-Reader-6-Tragbar-16GB-1400mAh-E-ink-E-paper-Buch-Black-Paperwhi/332790646489
• Searching the internet for "CPU Processor E200" and "e-book", gave me some results with a part number, BK-6006, like this one: https://www.amazon.com/ZY-Bk-6006-Book-Reader-Player/dp/B07KRBHWJP
• BK-6006 pointed me to the ODM's website, where the device is shown with a few different brands, such as Prestigio MultiReader PER3664. The ODM, Shenzhen ALSO Shuyuan Technology Co., Ltd. also has an Alibaba shop.
• The Prestigio homepage lists a more complete name for the CPU, Allwinner E200.
• The Allwinner E200 SoC is documented in more detail on https://linux-sunxi.org/E200.

This linux-sunxi.org has a short datasheet for this SoC, but not a programming manual. The SoC appears to be commonly used with the AXP199 PMIC, which isn't supported in mainline linux, but a datasheet is available.