Like you, I am unconvinced that a "sufficiently augmented" human would continue to value unaugmented humans, or infants.

Unlike you, I am also unconvinced it would cease to value unaugmented humans, or infants.

Similarly, I am unconvinced that it would continue to value its own existence, or, well, anything at all. It might turn out that all "sufficiently augmented" human minds promptly turn themselves off. It might turn out that they value unaugmented humans more than anything else in the universe. Or insects. Or protozoa. Or crystal lattices. Or the empty void of space. Or paperclips.

More generally, when I say I expect my augmented self's values to be incomprehensible to me, I actually mean it.

I am not entirely convinced that a vastly augmented mind would remember being a regular human in the same way that we humans remember what we had for lunch yesterday.

Mostly, I think that will depend on what kinds of augmentations we're talking about. But I don't think we can actually sustain this discussion with an answer to that question at any level more detailed than a handwavy notion of "vastly augmented" and analogies to insects and protozoa, so I'm content to posit either that it does, or that it doesn't, whichever suits you.

My own intuition, FWIW, is that some such minds will remember their true origins, and others won't, and others will remember entirely fictionalized accounts of their origins, and still others will combine those states in various ways.

There's not much there that is even worth remembering.

You keep talking like this, as though these kinds of value judgments were objective, or at least reliably intersubjective. It's not at all clear to me why. I am perfectly happy to take your word for it that you don't value anything about your hypothetical memories of infancy, but generalizing that to other minds seems unjustified.

For my own part... well, my mom is not a particularly valuable person, as people go. There's no reason you should choose to keep her alive, rather than someone else; she provides no pragmatic benefit relative to a randomly selected other person. Nevertheless, I would prefer that she continue to live, because she's my mom, and I value that about her.

My memories of my infancy might similarly not be particularly valuable as memories go; I agree. Nevertheless, I might prefer that I continue to remember them, because they're my memories of my infancy.

And then again, I might not. (Cf incomprehensible values of augments, above.)