Bought a K4 marked 'DEMO' and 'NOT FOR RESALE' in pristine condition for £5 at a car boot sale this morning. Used Kubrick to flash it and now it's a fully-functional, well-behaved, jailbroken Kindle. Just followed the instructions and the process went without a hitch.
System: Samsung Netbook booting from USB disk.
Thank you - I am impressed.