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Buildroot for 486

Here are the steps I used in order to get a brand new Linux version 4 kernel running on an old 486 DX computer. The setup is based on the Buildroot system for making embedded systems. The end result is the kernel with a very simple BusyBox based userland.

All the steps are based on the 2015.05 version of Buildroot, gotten from

Get the three necessary configuration files from Here.

First of all copy the configuration files into Buildroot and prepare it:

mkdir board/i486
cp i486_defconfig configs/
cp linux-4.0.4-i486.defconfig board/i486
cp extlinux.conf board/i486
make i486_defconfig

For any further changes to the configuration, use:

make menuconfig
make linux-menuconfig

Then build!:


I had to use extlinux as a bootloader, since neither syslinux nor GRUB worked correctly in my case. A Compact Flash card was inserted as /dev/sdd, and setup like this:

fdisk /dev/sdd # One primary partition, active, uses all space.
sudo cat /usr/share/syslinux/mbr.bin > /dev/sdd
mkfs.ext2 /dev/sdd1

Once the CF card is prepared, relative from the Buildroot folder, the files can be copied over:

mount /mnt/sdd1
sudo tar xf ./output/images/rootfs.tar -C /mnt/sdd1
sudo mkdir /mnt/sdd1/boot
sudo cp ./output/images/bzImage /mnt/sdd1/boot/
sudo cp ./board/i486/extlinux.conf /mnt/sdd1/boot/
sudo extlinux -i /mnt/sdd1/boot
umount /mnt/sdd1

The card is then ready to be used.

Topic: Configuration, by Kjetil @ 01/08-2015, Article Link