All of those things get covered in parts 2, 3, and 4 :)
There's... no part 2 in the post? And it's the latest blog post on the site, as far as I can see.
It does get linked at the very bottom, though admittedly it could be made clearer. https://astrid.tech/2026/03/24/1/swap-out-the-root-before-bo...
Oh, I see, the posts got published in the reversed order.
On the topic itself: wow, what a journey. And I personally fully support "come on, you should totally be able to just dump the system image onto your disk and reboot/exec it!"