Replace the kernel, when kernel is corrup

[Phongey]

Hi, is there anyway to replace the kernel through like linux or something

Here's why: I heard people talking about how the 10.5.4 Mac Software Update worked (they neglected to mention they were using vanilla) so I did it and Mac wont boot and yeah..... I have a 9.4.0 modbin kernel and system.kext (not on the mac partition) and I was wondering how I would go about installing the new stuff when Mac wont work...... I tried to replace it from Ubuntu but it told me that the device was read-only.

 

Or is there any way to access a shell? Cause I think I have a backup of 9.2.2 modbin kernel on the mac partition if I need it.