booting iBook G4 - kernel panic

Hi,

I had a PowerBook G4 (later model, Aluminum) on which NetBSD booted 
fine, but the GPU fried, as on many macs!
Now I couldn't find a working replacement, got another G4 but it has 
other issues and the two motherboards can't be swapped, didn't know the 
internal versions differed so much!
Now used G4 laptops are rare and expensive, I got a 12" G4 iBook, which 
has similar specs to the PowerBook.

the iBook looses date, but looks fine. It boots into MacOS, so the 
hardware, CPU, GPU are fine! good!

Fine I think, let's swap hard disk and continue hacking.
Silly idea: the iBook case is designed by a madman who thought that if 
everything is screwed together it was more robust, one need to take 
bottom and top cover, two shields just to get to the HDD!


I get a kernel panic very early. If it helps, I can try to retype or 
make a screenshot with my phone.
Or instead of a panic I see the framebuffer mangle up a bit after 
printing green characters

The kernel should be stock kernel I had installed, 9.2 or 9.3, I think 
the latter.
It should just boot, right?

Riccardo