ryans Oh, this happened to you too! I'm sorry to hear that, and at the same time it is interesting to confirm that someone besides me has had the same problem.

I am currently using my sea salt solution (see other thread) while waiting until I can get the Kindle into the hands of someone who can downgrade it for me.

Best of luck and keep me posted!

    Sunspark I don't know why the new firmware ruined the Kindle for me either. It's not a backlight, since mine is a Kindle basic without backlight. I've leave it to the tech experts to think about the possible technical cause of the problem.

      AGI How interesting! Simply changing the font was enough to restore your ability to use the Kindle! Do you have a Kindle basic, I assume? What was the old font, and how did you change it back? I am very eager to try this. (Others had suggested this to me in the past, but I wrote it off as a highly unlikely solution) Glad to hear about your success!

          daniels The original font is Caecilia, and it's still on your device. Simply select the font you wish to use from the settings in your book.

          Incidentally, a comment about fonts in general on any device, size them appropriately for the viewing distance. I don't have (and do need) reading glasses, so for handheld devices I need to make the font size quite small not large. This creates the effect of it being further away and thus easier for me to focus on at a close distance. If the letters are bigger, even tho they look nice, at a close distance my eyes cannot focus properly on larger letters anymore like they used to when I was younger. On a monitor it is the opposite, I need larger letters and I am further away from the screen. There are other technical things as well, but I wanted to mention the thing about size, because most people think they need bigger letters, but that's not actually the case every time.

              daniels Following @Sunspark 's suggestion I restored the font to Caecilia, and the discomfort disappeared. I cannot remember what the font had changed into. It could be that, had I pushed through, I would have got used to it, but why change something that works?

              Yes, my Kindle is not that old (2019 if I recall correctly), but still the basic model without LED lighting.

              Good luck!

                  Sunspark Thank you so much for the info about the font as well as for the advice about adjusting the font size! This is much appreciated.

                    AGI This is very encouraging, thank you for sharing!! I will give it a try.

                      7 days later

                      Highly recommend the keyboard kindles. they're pretty fragile, but only around $30 on ebay. any touch screen has an IR-LED

                        reaganry I had never heard of the keyboard. Is it an accessory I can attach to the e-reader I already have or would I have to buy a new Kindle equipped with a keyboard? Thanks.

                        • JTL replied to this.
                            15 days later

                            JTL pretty old, but they play audible books and have a little web browser.

                              a year later

                              I tested on LedEyeStrain group in Telegram the Kindle screen.
                              No pwm, but High modulation.

                              So use Kindle with an external light

                              I don't use Kindles but I have often had firmware updates ruin previously working devices.

                              Check on xda-dev's, sometime there are ways to hack the device and restore older firmware (I was able to rescue a Fire Stick this way)

                              dev