OTOH, you surely understand my point: It's generally not a very good idea to use the device online before having it jailbroken.
So the general rule for out-of-the-box Kindles in my point of view is:
1) Skip Wifi setting - leave it in airplane mode.
2) Connect it to a PC via USB. Is the Kindle drive accessible? No ---> Register your Kindle!
3) Copy the appropriate factory build firmware to the root of your Kindle drive.
4) Search for the UYK command.
4a) No UYK present (neither grayed out nor active)? ---> Register your Kindle!
4a) UYK menu entry is visible, but grayed out ---> Not the correct firmware file, or the Kindle is not downgradeable.
5) Do the UYK
...