Kobo

The on-screen message draws the line: previously downloaded books still open, but the device can no longer pull new purchases from the Kindle store. So he built a workaround, buy on Amazon, torrent a DRM-free copy, sideload over USB, and admits the purchase step now delivers no benefit whatsoever.

Not everyone sees malice. One reader whose own older Kindle still sideloads says the block only hits the store on end-of-life devices, whose ancient built-in browser was never going to last.

A finished EPUB validates fine, then renders as a blank or broken page on Kobo with no error. The cause is RMSDK, Adobe's proprietary engine inside Kobo, built around 2010 for EPUB2 — no flexbox, no grid, no CSS math functions. Modern CSS doesn't degrade, it crashes.

An indie who tried to license RMSDK directly: the email on Adobe's site answers nothing, no internal docs exist, the product was quietly sold off. Kobo is now rewriting its reader to drop Adobe entirely.