It's a blog! Mainly of book reviews.
The explanation has been there all along and I was just being dumb: There's a continuous local back-up "cortical stack" in your body. As long as this isn't destroyed when your body dies, you can remember your "death." It still isn't in reality possible to download this into a random body because your brain structure matters - you'd end up a different person. Personal clones might work? But the story is internally consistent, at least.