U-Boot is the booloader for the CORE9X25 board.

How to compile u_boot:

Install the cross compiler and the toolchain required on your Linux Ubuntu PC following this article (Tested on Ubuntu 12.04):

• Install the ARM9 cross toolchain to compile the Linux Kernel and AT91Bootstrap

Copy the CORE9X25 u-boot-at91-master.tar.bz2 to the PC /tmp folder(You can download it from here), then do the follow command to uncompress it:

~$ cd ~
~$ tar xvf /tmp/u-boot-at91-master.tar.bz2 -C .

This is a fork of the original Atmel version available on GitHub.

Move inside the at91bootstrap directory and launch Make:

~$ cd u-boot-at91-master/
~/u-boot-at91-master$ make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- distclean
~/u-boot-at91-master$ make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- at91sam9x5ek_nandflash_config

~/u-boot-at91-master$ make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- at91sam9x5ek_nandflash_256M_config

When the configuration in ready save and launch the compilation by typing:

~/u-boot-at91-master$ make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- -j4 at91sam9x5ek_nandflash

Copy the binary file u-boot.bin to USB Disk, and then you can insert it to the board to update the bootstrap file(refer to the Update the system image by USB Disk)

~/u-boot-at91-master$ cp u-boot.bin /media/usbhd-sda1/

Related links

• AT91Bootstrap home page
• GitHub repository of original AT91Bootstrap