U-Boot for the Nvidia Tegra Note 7

Quick Start

  • Build U-Boot

  • Boot U-Boot by loading it into RAM (coldboot)

  • Chainloading U-Boot from the vendor bootloader

  • Boot

Build U-Boot

U-Boot can be built in two forms: U-Boot with SPL, which is used for booting by loading directly into RAM and U-Boot without SPL, which can be flashed and chainloaded from the vendor bootloader.

To build U-Boot with SPL proseed:

$ export CROSS_COMPILE=arm-none-eabi-
$ make tegratab_defconfig
$ make

After the build succeeds, you will obtain the final u-boot-dtb-tegra.bin file, ready for cold booting by loading into RAM.

To build U-Boot without SPL adjust tegratab_defconfig:

CONFIG_TEXT_BASE=0x80A00000
CONFIG_SKIP_LOWLEVEL_INIT=y
# CONFIG_OF_BOARD_SETUP is not set
CONFIG_TEGRA_PRAM=y

After the build succeeds, you will obtain the final u-boot-dtb.bin file, ready for booting with fastboot boot or which can be further processed into a flashable boot.img.

Boot U-Boot by loading it into RAM (coldboot)

Done fairly simply by using fusee-tools (using run_bootloader.sh) and placing u-boot-dtb-tegra.bin generated on the previous step into fusee-tools dir. This method requires constant access to the host PC or payloader and can fully eliminate influence of the vendor bootloader onto the boot process.

$ ./run_bootloader.sh -s T114 -t ./bct/tegratab.bct

Chainloading U-Boot from the vendor bootloader

u-boot-dtb.bin has to be further packed into Android boot image form, where u-boot-dtb.bin acts as kernel, while dtb and ramdisk parts should not be included. Then the generated boot image can be flashed into the /boot partition of the tablet using vendor bootloader’s fastboot and will act as the bootloader of the last stage.

Boot

In both cases after U-Boot obtains control it performs search of extlinux.conf first on the dock USB device is available, then on MicroSD card if available and lastly on eMMC. If none of the devices above are present, then the device is turned off.

If during boot of U-Boot Volume Down button is pressed, the device will enter U-Boot bootmenu.