Downtown Doug Brown

For the next post in my series about upgrading my Chumby 8’s Linux kernel (here are links to parts 1, 2, and 3), I thought I’d look at what was involved in getting the reboot and poweroff commands working properly. I noticed pretty early during the development process that they didn’t work, which was pretty annoying.

The system is going down NOW!
Sent SIGTERM to all processes
Sent SIGKILL to all processes
Requesting system reboot
[   46.457580] reboot: Restarting system
[   47.458947] Reboot failed -- System halted

This meant that in order to restart the Chumby, I had to physically press a button to power it off and again to power it back on. As you can imagine, this got old really fast during development. For that reason it was one of the earliest things that I got working.

I actually implemented it in U-Boot first, but I thought the Linux side of it would be more fun to share. If you want to see what was involved on the U-Boot side, see this commit from my fork of U-Boot.

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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.

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