Make Buildroot (embedded Linux) for Raspberry Pi 2

Buildroot is a simple, efficient and easy-to-use tool to generate embedded Linux systems through cross-compilation.

To make sdcard image to run Buildroot on Raspberry Pi 2 using default config:

- Visit https://buildroot.org/ to download the latest stable release (2016.02 currently) - buildroot-2016.02.tar.gz.

- Unpack the downloaded file:
$ tar zxvf buildroot-2016.02.tar.gz

- Switch to the unpack folder:
$ cd buildroot-2016.02

- Copy the default config for Raspberry Pi 2:
$ cp configs/raspberrypi2_defconfig raspberrypi2_defconfig

- make:

$ make raspberrypi2_defconfig

$ make

- After make finished, buildroot-2016.02/output/images/sdcard.img will be created. It's the image file for Raspberry Pi 2.

- In my case, copy the sdcard.img file to Windows, and write to SD using Win32DiskImager.

- Then insert to Raspberry Pi 2 and boot-up. By default, the user "root" have no password.