If you had no attempts on device_open, the cached time was not set.
Then your next operation would instantly time out.
Solution => set time_cache on socket open.

... I wish more libraries did this!

Remove 8-bit eb_address_t support.
... The config space is at least 16 bit wide.

   inline
   unnamed unions
So, change all occurances for improved portability.

Split config and non-config handlers to distinct methods.

Allocation could cause heap resize => invalidates all pointer dereferences.

Start address scan using high bit of config space

Added guards for null callbacks.

Tag implementation with flag
Tag all private methods as private