U-boot

source

• git clone https://github.com/gonzoua/u-boot-pi.git
• svn co file:///var/svn/rpi_uboot/trunk

toolchain

• git clone https://github.com/raspberrypi/tools

build

• export ARCH=arm
• export CROSS_COMPILE=arm-linux-gnueabi-
• make rpi_b

prepare SD card for your u-boot

• ./tools/mkimage/imagetool-uncompressed.py u-boot-pi/u-boot.bin
• cp kernel.img RASPBIAN_BOOT_PARTATION

boot to kernel from USB

• prepare your zImage in usb disk, and you should try another usb port if not working while load to ram
• U-Boot> usb start
  • use usb sub-system to check avaliable dev and part
    • U-Boot> usb dev
    • U-Boot> usb part {dev}
  • use ext2load to check where your zImage existed or not
    • U-Boot> ext2ls usb {dev}:{part}
• U-Boot> ext2load usb {dev}:{part} ${loadaddr} zImage
• U-Boot> bootz ${loadaddr}

reference

• RPi U-Boot