I'm selling my Waterproof Kindle Paperwhite 4 WiFi 8GB (no-ads), it's running firmware 5.10.1.3, and is unscratched and in great condition front and back.
It's been jailbroken (though you are free to reset this and skip to the latest firmware if you want), and has the book cover screensaver enabled.
£45 to anyone in the UK.
