QUOTE(Samph @ Jul 21 2009, 12:53 AM)

Assuming I was able to go out and find a Xbox 360 with kernal 4532 or 4548 (or earlier) and run the orginal King Kong shader exploit, would it be possible to be able to run unsigned .xexs and homebrew etc on the console?
It's possible in theory, but the work required to make this actually work has not been done.
QUOTE
How would this be done?
If it is possible why has no body done it?
The problem is that once the exploit happens, the console is in a fully booted state with the regular kernel and hypervisor loaded, but with the flow of execution on the processors diverted to be running our code in hypervisor mode. To boot up a patched version of the hypervisor, kernel and dash which do not check signatures, the console needs to be put back to a state that more closely resembles the state it's in at the time it powers on. Some people were working on a rebooter that would achieve this, but it was not finished and there is no ongoing public discussion of the project - it was not able to correctly reboot to even an unmodified version of the system last time it was discussed.
It's not a (comparatively) simple matter of just patching a bit of code in memory and carrying on, which is more or less what tools like nkpatcher do for the original xbox - the entire stack of hypervisor, kernel and dash needs to be happy that it's in the state it's supposed to be in.