How to make a buildroot rootfs for MIPS CI20 -


To make a buildroot rootfs tarball run

git clone git:// buildroot
cd buildroot
make qemu_mipsel_malta_defconfig
make menuconfig

The malta_defconfig is a good basic start and boots on the ci20.

Enable the following options in buildroot

Toolchain -->
    Toolchain type -->
        External toolchain
        (download or select path of your preinstalled toolchain)
Filesystem images -->
    cpio the root filesystem
    tar the root filesystem
 Kernel -->
    <Disable the Linux kernel option. We built our own>

Exit and Save the configuration.


Once the build has finished (can take quite some time. You are making an OS) you should have the following outputs



That is basically it.

When you followed the steps on

Mount the ext4 partition on your sd card using

sudo mount /dev/sdx1 /mnt

where sdx is your sd card writer (find using lsblk).

Extract the rootfs.tar using

sudo tar -xvf output/images/rootfs.tar /mnt/

At the u-boot prompt, you might want to check your bootargs being passed to the kernel.


They should be something like this bootargs=console=ttyS4,115200 console=tty0 mem=256M@0x0 mem=768M@0x30000000 clock_ignore_unused

You need to add the following to your bootargs

root=/dev/mmcblk0p1 rootwait devtmpfs.mount=1

This can be done via

setenv bootargs console=ttyS4,115200 console=tty0 mem=256M@0x0 mem=768M@0x30000000 clock_ignore_unused root=/dev/mmcblk0p1 rootwait devtmpfs.mount=1

Note: Do check your serial console. You might be using ttyS0 instead of ttyS4

If you want to save the environment for uboot to run every time.




And enjoy :).

You can extend the basic configuration of buildroot now. Simply go to the root folder where you cloned the buildroot repository.

make menuconfig

Select any that you want for target packages. Look closely enough and you will find an X window manager too :) Save and exit the menuconfig.

Run make again. And extract the rootfs onto your sd card ext4 partition again.