Buildroot Linux for 68k Macs

Pre-configured Buildroot Linux for 68040-based Macintosh.

To setup the Buildroot environment, run:

./setup.sh

Now you can configure further using the standard Buildroot methods, please see the Buildroot documentation.

As an example, to build images simply run make:

make

The first build will take quite some time.

By default, a kernel, ramdisk, and ext2 volume will be built into the images directory.

The images are configured to DHCP using onboard ethernet and start an SSH server. There is only a root user with no password. Additional packages can be installed by configuring Buildroot.

For machines with smaller memory configurations, you can switch the kernel to build for size (-Os), disable kernel features (additional filesystems, IPv6, etc), and disable software packages. The default configuration will run well on systems with 64MiB, but may work on smaller systems.

First boot will be very, very slow as the SSH host keys will be generated. Let it sit, it is not frozen.

Usage

To boot these in Qemu, run:

$ qemu-system-m68k -boot d \
    -M q800 -m 256M -rtc base=localtime \
    -net nic,model=dp83932 -net user \
    -append "root=/dev/sda rw console=ttyS0" \
    -kernel images/vmlinux \
    -drive file=images/rootfs.ext2,format=raw \
    -nographic

To boot on a real computer, use Penguin. The Linux/mac68k Project has a useful FAQ.

Roughly, you can do the following to boot Linux from memory as a test. This will require a large amount of memory (64MiB+):

1. Copy vmlinux and rootfs.cpio.lz4 to your Mac.
2. By default, Penguin is not configured to use as much memory as we need to load modern, larger Linux kernels and ramdisks.
   • On your 68k Mac, select the Penguin app and do File -> Get Info.
   • Set the Minimum and Preferred memory to something large, like 50000. This ensures the app can allocate enough memory to load the entire kernel and ramdisk.
   • Close the Info window.
3. Open Penguin and select File -> Settings…. Select the Kernel tab.
4. Choose a kernel file and select vmlinux.
5. Check the RAM Disk box and select rootfs.cpio.lz4.
6. Select the Options tab.
7. In the command line, put root=/dev/ram.
8. Click OK, save the settings if you like.
9. Select File -> Boot Now

If you'd like to install to disk, you'll need to copy the rootfs.ext2 to a new ext2 partition on a SCSI disk. You can select this as the boot device by modifying the command line to put root=/dev/sda2 rw, where "sda" is mapped to the SCSI ID (a=1, b=2, etc) and the digit is the partition number.