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[samoflange]

I couldn't accept that this won't work when so many similar systems do, so I spent a week poking around at the system, documenting the architecture and layout of this system vs the ones that do. I actually went so far as to start writing a custom driver, thinking that was all that would solve this. (I seriously have most of a functioning driver for the TAS3004. My head hurts)

So I bought and started poking around at a 1.2 ghz 12" iBook because audio works on it. It is so similar, but also has some differences that stood out. Parts of this system's firmware are still very similar to the older supported systems, yet still running on the Intrepid platform and with a 7447a G4 and a TAS3004 sound system. I think this system is the key to fixing a lot of problems.

Open Firmware hurts my soul, so I enlisted the help of Claude to take the information I found, and spoofed some of the device names and addresses in open firmware to match the iBook. It worked! I strongly suspect this can be done to fix some of the weirdness with the other aluminum powerbooks, and will be looking into this further. I'll also be sharing some of the information I found to make this work, because a lot of it was incredibly difficult to find. I even had to decompile a few bits of the OS with Ghidra and dig around.

I have no idea which other systems this specific script will work on, but I have tested it fairly extensively on a 1.33 ghz Powerbook 5,4. The 5,3 is so similar I am almost certain it will work there too. It's probably worth at least testing on any aluminum powerbook.

This should also offer a solution to things like inverted headphone switch polarity, etc, but I don't really have much hardware to poke around at and find out.  I am almost certain audio can be made to work on most Aluminum powerbooks and iBooks with this method.

I'm attaching 2 scripts. One that is just a direct clone of the iBook hardware spoofed to the powerbook. Another that includes some additional information to activate the inputs. The microphone seems to work, headphone jack auto detect works, volume controls work. I have not done much testing with inputs, but they appear.

I have encountered a few bugs that I'm looking at. There's some crackling occasionally. Most likely because the EQ settings for the iBook and Powerbook aren't an exact match. I have also encountered a bug where it crashes every other boot. This seems to be related to a write to the sound preferences, and can be solved by locking that preference file. It's some sort of extension conflict, because booting with extensions off seems to solve it.

TLDR; I think I found the fix for sound on most iBooks and Aluminum Powerbooks.


Just drop one of the scripts at the root of your hard drive, and set open firmware to boot from script.

boot holding command+option +OF

then type:

setenv boot-device hd:\bootscript
reset-all

I'd be really interested to hear if this works for others and which systems you've tried. And if anyone can figure out what's causing that crash.