Mac OS 9 Lives
Mac OS 9 Discussion => Mac OS 9, Hacks & Upgrades => Mac OS 9 on Unsupported Hardware => Topic started by: knobsnswitches on October 14, 2026, 01:52:23 PM
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I got my PowerBook 12" working in Mac OS 9 yesterday, but unlike other reports I have seen, I had no sound at all, rather than speakers requiring headphones attached to work. There was nothing shown in the Sound control panel outputs (or inputs section) for that matter.
Long story short, Claude, the Mac OS 9 expert, helped come up with an open firmware script that fixes my sound issue, and the headphones / speakers both work as expected.
Here is the script and an explanation. (Claude offered to write a forum post about the whole thing. How lazy do you have to be? How long til forums are just bots talking back and forth? Pretty hollow, I admit, when I couldn't fix this on my own).
Note, i have 2 partitions on my PowerBook, if you just have one, you can ignore the partition info and use "hd:1" instead of "hd:10" as explained below.
1. Save the text below as a plain-text file named soundFix (no extension) at the top level of your OS 9 disk. Mac line endings from SimpleText are fine.
2. Change hd:10 on the "boot" line to your OS 9 partition. To find it, run "printenv boot-device" in Open Firmware after booting OS 9, or try "dir hd:10,\" and nearby numbers until you see your System Folder.
3. Boot into Open Firmware (Cmd-Opt-O-F) and test it with: boot hd:10,\soundFix
4. To run it on every boot: setenv boot-device hd:10,\soundFix and then reset-all. Choosing a disk in the Startup Disk control panel (OS 9 or OS X) overwrites boot-device, so run the setenv again after that.
<CHRP-BOOT>
<COMPATIBLE>
MacRISC MacRISC2 MacRISC3
</COMPATIBLE>
<DESCRIPTION>
PowerBook6,1 OS 9 sound fix (soundFix)
</DESCRIPTION>
<BOOT-SCRIPT>
dev /pci@f2000000/mac-io@17/i2s@10000/i2s-a@10000
" i2sbus" encode-string
" compatible" active-package get-package-property 0= if encode-bytes encode+ then
" compatible" property
device-end
dev /pci@f2000000/mac-io@17/i2s@10000/i2s-a@10000/sound
" feature index 0 model Proj16PowerControl" encode-string
" feature index 1 model Equalizer" encode-string encode+
" detect index 0 bit-mask 2 bit-match 0 device 2 registry-name extint-gpio15 model GPIOGenericDetect" encode-string encode+
" detect index 1 bit-mask 2 bit-match 2 device 2048 registry-name extint-gpio4 model GPIOGenericLineInDetect" encode-string encode+
" input index 0 icon-id -16521 name-id -20630 port-connection 1 port-type 0x6C696E65 zero-gain 0x00000000 model LineInput" encode-string encode+
" input index 1 icon-id -16521 name-id -20532 port-connection 4 port-type 0x696D6963 zero-gain 0x00000000 model InternalMic" encode-string encode+
" input index 2 model NoInput" encode-string encode+
" output index 0 device-mask 2 device-match 2 icon-id -16563 name-id -20524 port-connection 1 port-type 0x6864706E model OutputEQPort" encode-string encode+
" output index 1 device-mask 2 device-match 0 icon-id -16563 name-id -20525 port-connection 2 port-type 0x6973706B model OutputEQPort" encode-string encode+
" sound-objects" property
device-end
boot hd:10,\\:tbxi
</BOOT-SCRIPT>
</CHRP-BOOT>
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Long story short, Claude, the Mac OS 9 expert, helped come up with an open firmware script that fixes my sound issue, and the headphones / speakers both work as expected.
NOICE! Claude is indeed the Mac OS 9 expert ;D Can you turn this into a drop-in system extension? With sound fixed, it looks like Sleep is the only thing remaining to tackle for this model.