It's never been very clear what "open" means, but I'm pretty sure it doesn't mean "untrained persons can perform major surgery risk-free".
http://wiki.cyanogenmod.com/index.php?title=Howto:_Nandroid_...
"if I was running a jailbroken iPhone, I'd just restore it with iTunes, and it would be factory-fresh with known software."
Apple tells you not to jailbreak, but they'll happily let you back in the house if you've gotten yourself into a mess. Google are telling power users that their OS is the hacker-friendly one, but leaves minefields for anyone who takes them at their word and tries to do what the author did.
With Android, "Open" means you must perform major risky surgery on your device to install software that hasn't been approved by your carrier.
With iPhone, "Closed" means you can always install the latest OS as soon as it's released.