Customizing the startup chime on a 1999 G3 iMac

If you've been reading my blog for a while, you might remember back in 2012 when I changed the startup sound on my Power Mac G3 (Blue and White). That was a fun introduction to the Forth programming language. I had to reverse-engineer just enough of Apple's firmware update script to understand what was going on.

Recently, Aidan Halpin, a reader of this site, asked me if I could do the same kind of startup sound customization on his iMac. This particular iMac is officially known as the iMac (Slot Loading)" and has a model identifier of PowerMac2,1. As you can guess from the name, it has a slot-loading CD-ROM drive unlike the original iMac that had a laptop-style tray-loading drive. By the way, Aidan's iMac is special because it has a PowerPC G4 processor soldered onto the logic board instead of the original G3.

He sent me Apple's last firmware update for this model: iMac Firmware Update 4.1.9. I went to work looking at the update contents to see if I could figure out how to modify the chime the same way I did with my Power Mac G3. I thought it would be fun to take everyone along for a ride and show exactly what was involved in changing the sound. And of course, this post wouldn't be complete without also sharing the code for the utility I created to inject the new chime into the firmware update file.

This is an insane amount of work for something that doesn't really matter in the end. I love it.