@knc1: IIRC, those set of keys (or 'leaves', as elektra calls them, IIRC) haven't changed in quite a while. Some of that ended up in KindleTool code comments

.
I can also confirm that bind-mounting over the cramfs db works, but you have to be careful of the timing and the sanity of the file, since any kind of issue will soft-brick the device (this trick is used by USBNetwork when enabling the per-device MAC support, for instance).
On the plus side, you can be much more granular and just bind-mount a single leaf or a single subtree instead of duplicating the whole tree.