I found this guide to converting an old Kindle 4 to display anything from the web super useful. https://matthealy.com/kindle I bought another 3 used kindles for $20 each after getting it to work.
You can also use the built-in web browser without jailbreaking Kindle: https://github.com/matopeto/kindle-weather-dashboard or my https://github.com/niutech/kindle-dashboard