Glenn Fleishman discusses the challenges of sideloading his newly released audiobook on an iPhone. Initially, he recorded it in MP3 format, but faced issues with chapter markers in Apple's Books app. He discovered that converting the file to AAC (.m4a) format was necessary for compatibility. However, syncing audiobooks requires using Finder, as iCloud sync is not applicable for sideloaded content. He provides detailed steps for syncing audiobooks via Finder and suggests that podcast apps may offer easier sideloading options. Overall, the process is depicted as outdated and cumbersome.
https://sixcolors.com/post/2025/08/apple-makes-it-hard-to-load-audiobooks-purchased-elsewhere/