I finally gave into the year-long temptation to get an old Sony eReader (the PRS-300 to be exact). I got it for 10€, with a broken battery. There were some books on it as well. It's very similar in size to older 6 inch reader, a little less wide. Excited to read my first book on it after changing the battery. Thanks to @ifixcoinops for the inspiration
I love when custom Firmware from 2011 is still available, just works and really easy to install 
I noticed something weird with the PRS 300. The letters start fading after a few page turns, as if the ink is running low. It's really distracting. Can this be fixed/changed? #prs300 #ereader #eink
I wrote a little something about the Sony PRS-300 on my blog:
https://blog.not-outdated.com/entries/prs300.html
The Sony PRS-300 (and other 5'' eReader)

I talk about my reading experience with the Sony PRS-300, putting on custom firmware, the process of swapping the battery and sewing an envelope-style pouch. I'm also comparing it to two other 5 inch eReaders: the Pocketbook Mini from 2013 and the Xiaomi Mooan Inkpalm 5 from 2022.

@becca @jollysea is this to do with the the refresh rate? I think on my e book you can save battery by not refreshing every page. It's in the settings.

@Tattooed_Mummy I suspect that, but couldn't find any related setting. I'll look again later, maybe its under power / battery settings.

Edit: couldn't find anything

@becca I have a PRS-600 which might have a similar screen like yours. And I think I know the reason for your issue: You have taken these pictures outside in the sun. Mine gets weaker and weaker black pixels, the warmer the screen gets. So much, that I cannot use it in direct sun. Putting it into the shade an letting the screen cool down immediately solves the issue.
@bastelwombat interesting! I didn't think of that since the picture on the left was taken after the picture on the right. But now that I am inside, I feel like the effect wore off and it doesn't fade that much. Thanks for the hint
@becca @ifixcoinops oh man, what a blast from the past. The sony reader was the first ereader I ever owned. ​​ I was pretty sad when it died. It’s cool to see some still kicking around.
@becca I was just looking at a 300 on eBay that had a knackered battery and some screen ghosting and going "hmmmm"