I'm not sure what you mean, the iOS boot loaders are encrypted and signed. There is a fairly strict chain of trust running from the physical ROM on the chip its

I'm not sure what you mean, the iOS boot loaders are encrypted and signed. There is a fairly strict chain of trust running from the physical ROM on the chip itself to the apps on the home screen, with each stage signed and verified. Some are "encrypted" (all are when installing, but some in flash storage as well), all are signed. At the current time, there is no known vulnerability in this chain of trust for iOS devices released after September 2010. Comparing this to Android "locked" boot loaders or Windows 8 is severely devaluing the security infrastructure Apple has in place here. I'm not going to even argue they Apple has done a good job — compared to something like the Xbox 360, they clearly haven't — but it's a step up from what you are describing. Also, at this time, iOS is the only operating system that will run on iOS devices released after June 2008. The iPhoneLinux project attempted ports to the original iPad, but s far has only been successful on devices through e iPhone 3G.