No registration with amazon is needed for the device to function properly.
You need to change a few files (AFTER BACKUP, otherwise you won't be able to update in the future):
It is quite straightforward, I have one "virgin" K3Wifi which was never activated with amazon, but I am still able to use the internet and upload books to it without it connecting to amazon or using it's network.
Since the files all have "confidential/copyright" I won't be able to post them here, but when you see the files on your own kindle, It will be obvious what to change.
PS. don't forget to white-list the whole internet

The files I changed in order to have the device divorced from amazon:
Code:
Etc/hosts
etc/kdb.src/luigi/system/deamon/testd/proxy_host
etc/kdb.src/luigi/system/deamon/wand/NETWORK_TEST_DOMAIN
etc/sysconfig/ntp
Opt/amazon/ebook/config/browser_wv.conf
Opt/amazon/ebook/config/framework.fiona.conf
Opt/amazon/ebook/config/ServerConfig.conf
Opt/amazon/ebook/config/wrs.ini
Regards,
EqX