I remember my Nokia N91 which had a 4GB version of one of these tiny HDDs, blew my mind at the time.

Man do I miss the N-series, I had so many good phones in that era.

Worked on that phone. I diagnosed if music player cache was working by putting back of phone to my ear and listening for seeking clicks from hdd

First time hearing about this. I just looked up that drive. That's genuinely amazing, and kind of adorable.