Following on from running MacOS on a Pippin console (see http://www.applefritter.com/node/view/3510), I've been trying to install Linux. I've been lucky enough to buy a ROM 1.3 update and PCI slot adapter off eBay so the Pippin that I'm using is almost as up to date as they get. I'm limited to 13MB of RAM (1MB of the 14MB is reserved for video RAM) which is enough to run Linux and a few services but not enough to install it from one of the standard PPC distros...
Naturally I have ignored all information about minimum memory sizes and supported platforms because those rules don't apply. Pippin hardware is strange; according to TattleTech or any other reporting utility, it is a combination of NuBus and PCI architectures. Open Firmware is not 1.0.5 (ROM 1.3 updates it to something identified as "PipPCI2") but I can't generate an OF console prompt. However Linux can run on some of the (awful but similar) 5xxx and 6xxx PowerMacs so it ought to run on a Pippin if I can work out which kernel to use.
I've spent three or four evenings investigating the three Old World boot loaders (Apple Mklinux, BootX, miBoot) and a variety of installer kernels for popular distros (I have no intention of rolling my own at this time). BootX seems the most promising loader and displays useful diagnostics if Command-Option-O-F is pressed on startup. miBoot doesn't report as much as BootX but here's a sample of what happens when I try to boot from a Debian Woody (miBoot) floppy (see http://www.applefritter.com/node/view/4906). Whichever kernel I use, I find that the Pippin hangs on "Entering PPC Supervisor" or earlier.
I have a horrible feeling that none of the standard ram-based installer kernels will ever work on a Pippin. BootX reports that ramdrive size and location are both nul sized, whatever boot loader options are applied; MacOS is also unable to create a ramdrive on the Pippin. Alas this is consistent with Pippin architecture which uses the driver .rdrvr to mount the built-in the 128KB flash storage, thus, by my theory, preventing later use of a ramdrive. Unfortunately I don't yet have a full BootX diagnostics report because I'm too lazy to configure a serial console until it is absolutely necessary. I'll also have a look at hacking the Pippin System Enabler to disable activation of the built-in flash drive.
One of the NuBus Mklinux sites has an interesting recipe for installing updates on a RAM challenged Mac so perhaps one of the more experienced Linux users here can help me out with an alternative installation procedure. My idea is to install a small footprint (eg Debian Woody) workstation onto an external disk using another PPC Mac and then attach the disk to the Pippin. Can I use a NuBus Mac or does it need to be PCI? I don't know which kernels will work with the Pippin. Can I install a selection of kernels and then work my way through them using the boot loader? For Old World Macs, is the kernel that is installed on the Mac system disk the "active" kernel when Linux has booted or is the OS transferred to a kernel on the Linux system disk? Can I install Linux onto a Zip cartridge initially and then use dd or a blind SCSI copy to copy the installation partition to a hard disk?