Repurposing an old Kindle 4

My kid found an old Kindle 4 in a drawer and asked if he could use it. Nobody remembered why it was discarded - it seemed to work fine. The mystery was solved when we tried to add new books: Amazon had stopped supporting this model years ago.

The solution was simpler than expected: a jailbreak later the kindle works just fine with ebooks bought outside of Amazon and transferred via USB using Calibre.