I installed a pkg and my Mac won't boot. How to "undo"?

Question

I downloaded the Magic Trackpad pkg from http://support.apple.com/downloads

I then followed this guide to rebuild the official package without the 10.6.4 requirement.

He warned me to "use at my own risk" but it seemed straight forward enough.

Now my Mac (10.5.8) won't boot. I tried Cmd+Alt+P+R to flash PRAM but that didn't help. What can I do?

Answer 1

I'm pretty sure your system will have to be reinstalled to repair this damage. Boot from the installer DVD, and do an archive install on you HD; then reinstall all system updates, and any 3rd party software that doesn't work after the reinstall (simple apps shouldn't be affected by an archive install, but anything that hooks into the OS parts of the file system will have to have those parts reinstalled to work right).

If you have a backup, you may be able to recover from that instead.

What's happened is that the Magic Trackpad package has replaced a bunch of parts of your OS -- mostly those having to do with bluetooth, e.g. bluetooth drivers, the bluetooth preference pane, etc etc etc -- with newer versions that won't work right on your OS version and/or your CPU. 10.6 dropped support for PowerPC CPUs, so if you have a PPC Mac the new components are going to be completely nonfunctional for you.

Answer 2

As the article clearly says:

CMD+ALT+P+R (PRAM reset)

CMD+ALT+N+R (NVRAM reset)

and finally…

Use the OS X Boot DVD to Reset Firmware.