U-Boot

Support for sunxi devices is increasingly available from upstream U-Boot. This page describes that support.

To know if your device is supported in U-Boot, check out the respective device page. Here is the list of all devices supporting mainline U-Boot.

A changelog is available here.

We have a separate page for the legacy sunxi branch of U-Boot.

This document is mainly for 32bits ARM device. Differences for ARM64 are only mentioned in the Compile U-Boot section. For more info see directly board/sunxi/README.sunxi64 in uboot sources.

= Status Matrix =

The goal of this matrix is to give an easy view of work on each SoC worked on by linux-sunxi.


 * MMC is for ability to boot from sdcard
 * USB is ability to connect USB devices (like ethernet dongle)
 * NET is ability to boot from TFTP
 * HDMI is ability see the boot screen through HDMI
 * UART is ability see the a boot screen through serial console

= Compile U-Boot =

Get a toolchain
If you haven't done so before, get a suitable toolchain installed and added to your PATH.

You may also need to add some additional packages to build U-Boot: apt-get install swig python-dev

Get the Device-tree Compiler
Depending on your desired U-Boot version, a sufficiently up-to-date dtc may be required. (The build process will error on an outdated dtc, and request you to upgrade it.) The installation of dtc is described in the Device tree article.

If you are going to build a Linux kernel alongside U-Boot, it might also be worth to examine the kernel sources - as they come with dtc included under.

Clone the repository
You can clone the u-boot repository by running: git clone git://git.denx.de/u-boot.git

Determine build target
Go to your u-boot tree and search in the directory configs/ for your board, the file name looks like _defconfig.

So, if your device is Cubieboard2 your build target is Cubieboard2_defconfig.

Build
Arm Trusted Firmware (arm64)

In order to build U-Boot for a arm64 device you need to build Arm Trusted Firmware (ATF) as a prerequisite first. Change to your needs. PLAT=sun50i_a64 for example is suitable for H5 and A64 devices. (See board/sunxi/README.sunxi64 in uboot sources for more infos.) git clone https://github.com/ARM-software/arm-trusted-firmware.git cd arm-trusted-firmware make CROSS_COMPILE=aarch64-linux-gnu- PLAT= DEBUG=1 bl31

When you have determined what  just configure U-Boot with a suitable default configuration. Use menuconfing to play with the settings if you feel like it and then just build it:

armhf make CROSS_COMPILE=arm-linux-gnueabihf- _defconfig make CROSS_COMPILE=arm-linux-gnueabihf- menuconfig make CROSS_COMPILE=arm-linux-gnueabihf- arm64 make CROSS_COMPILE=aarch64-linux-gnu- BL31=/build/sun50i_a64/debug/bl31.bin _defconfig make CROSS_COMPILE=aarch64-linux-gnu- BL31=/build/sun50i_a64/debug/bl31.bin menuconfig make CROSS_COMPILE=aarch64-linux-gnu- BL31=/build/sun50i_a64/debug/bl31.bin

(When compiling natively, omit the CROSS_COMPILE=… )

When the build has completed, there will be u-boot-sunxi-with-spl.bin available in your u-boot tree. The installation step will instruct how to install this on the installation media (e.g. a SD card), but first U-Boot needs to be configured.

= Configure U-Boot =

This article provides a collection of various scenarios for booting with U-Boot.

Boot
For getting these bits loaded onto the hardware, please refer to the respective howto:
 * SD Card
 * NAND
 * SPI NOR Flash
 * USB OTG
 * Ethernet
 * Fastboot

Booting with boot.cmd
For booting from SD with mainline U-Boot, the recommended way is:


 * create a file boot.cmd on the first partition (also check Kernel arguments for extra 'bootargs' options):


 * If you also want to use an initramfs, please refer to the Initial Ramdisk article for details.


 * Substitute zImage in place of uImage in the commands above, and then use the bootz command instead of bootm.

mkimage -C none -A arm -T script -d boot.cmd boot.scr
 * boot.cmd isn't used directly, but needs to be wrapped with uboot header with the command:

Booting with extlinux.conf
Mainline U-Boot also use syslinux/extlinux as payload.

You need to install the boot configuration file extlinux.conf in an ext2/3/4 partition of SD card and U-Boot will find and execute it. This is conceptually identical to creating a GRUB configuration file on a desktop PC.

Example extlinux.conf: TIMEOUT 100 DEFAULT default MENU TITLE Boot menu

LABEL default MENU LABEL Default LINUX /zImage FDT /sun4i-a10-marsboard.dtb APPEND root=/dev/sda1 rootwait console=tty0 console=ttyS0,115200n8

LABEL exit MENU LABEL Local boot script (boot.scr) LOCALBOOT 1

Setting u-boot environment variables
There is a difference in setting environment variables between the boot script and the U-Boot shell.

Inside the shell you would set, for instance: setenv root /dev/sda1

But in the script you would use: root=/dev/sda1

NAND
Example U-Boot environment, as found in  from a stock android U-Boot environment partition

bootdelay=0 bootcmd=run setargs boot_normal console=ttyS0,115200 nand_root=/dev/nandc mmc_root=/dev/mmcblk0p4 init=/init loglevel=8 setargs=setenv bootargs console=${console} root=${nand_root} init=${init} loglevel=${loglevel} boot_normal=nand read 40007800 boot;boota 40007800 boot_recovery=nand read 40007800 recovery;boota 40007800 boot_fastboot=fastboot

NFS
Recent version of U-Boot are able to boot from NFS as well as TFTP, but you have to get rid of the automatic setup of FTP. Check Ethernet for more information.

FB console
To get U-Boot output shown on the built-in framebuffer driver (currently, HDMI only at 1024x768), add the following to your boot.cmd: setenv stdout=serial,vga setenv stderr=serial,vga The default environment has these values set as well.

LCD Settings
There is a separate wiki page about configuring LCD in U-Boot.

= Install U-Boot =


 * Convert the boot.cmd to boot.scr using mkimage:

armhf mkimage -C none -A arm -T script -d boot.cmd boot.scr arm64 mkimage -C none -A arm64 -T script -d boot.cmd boot.scr
 * Copy the bootloader to the installation media

dd if=u-boot-sunxi-with-spl.bin of=/dev/sdX bs=1024 seek=8


 * copy kernel files to the first partition
 * For a 3.4 kernel you need uImage (linux kernel) and script.bin (binary representation of FEX).
 * For a device tree based kernel ("mainline", 4.x) you need the kernel image (uImage, zImage or Image) and the device-specific .dtb file (the one referenced in the ${fdtfile} above) that is generated as part of your kernel compilation.

Look at Manual build howto for more details.

= Troubleshooting =

USB 1.x, USB keyboards (U-Boot < v2015.07)
U-Boot v2015.07 and later shouldn't have problems supporting mixed USB 1.x/2.0 devices. OHCI and EHCI no longer conflict with each other (after the switch to device model).

Previous U-Boot versions (v2015.04 and older) have a problem supporting both USB 1.x (OHCI) and USB 2.0 (EHCI) at the same time - the latter includes the SUNXI_EHCI driver for Allwinner boards.


 * Unfortunately, this also affects many USB HID / keyboard devices which would not be detected properly by U-Boot. The typical message in this case is "cannot reset port N!?", where N is whichever USB port those devices were attached to.

See: http://lists.denx.de/pipermail/u-boot/2015-January/200162.html.

U-Boot 2015.07+ won't start
If you're using a recent (device model based) U-Boot, and the SPL just hangs after initializing the DRAM ( or something similar), chances are that your main U-Boot binary may be missing DTB information / a proper device tree. Depending on the (possibly outdated) instructions you followed: double-check that you're not incorrectly using u-boot.bin instead of u-boot-dtb.bin, or u-boot.img instead of u-boot-dtb.img.

Legacy kernel won't start

 * If your 3.4.x kernel refuses to boot / gets stuck right after "Starting kernel ...":
 * Double-check that bootm_boot_mode is set to "sec"! (see above)
 * For U-Boot 2018.09-rc1 or later, set CONFIG_ARMV7_LPAE=n in .config or apply https://patchwork.ozlabs.org/patch/1058338/
 * If you don't have a serial console and only use VGA/HDMI/LCD, then it might be also the case of "Unrecognized/unsupported machine ID" (see below).

Unrecognized/unsupported machine ID
The sunxi-3.4 kernel may fail to boot with one of the following error messages on the serial console (but this message is not visible on a HDMI monitor or a LCD display!): Error: unrecognized/unsupported machine ID (r1 = 0x10001008). Error: unrecognized/unsupported machine ID (r1 = 0x1000102a). Error: unrecognized/unsupported machine ID (r1 = 0x100010bb). In this case either upgrade to a recent stage/sunxi-3.4 kernel (github branch) - or try to "Enable workarounds for booting old kernels" in U-Boot:
 * or, the option is located under "ARM architecture". (Make sure to rebuild your U-Boot after changing it.)

If upgrading to stage/sunxi-3.4 is not an option (i.e. using some old and very much diverged sunxi-3.4 fork is really necessary), then the following patches can be cherry-picked (= selectively merged as a set ): wget https://github.com/linux-sunxi/linux-sunxi/commit/5052b83aa44dc16d6662d8d9d936166c139ad8c5.patch wget https://github.com/linux-sunxi/linux-sunxi/commit/9a1cd034181af628d4145202289e1993c1687db6.patch wget https://github.com/linux-sunxi/linux-sunxi/commit/c4c4664ed1a2f35e54a33ae4e65f517721ff43b5.patch wget https://github.com/linux-sunxi/linux-sunxi/commit/ade08aa6e5249a9e75a97393e86c250b2bcb3ec8.patch wget https://github.com/linux-sunxi/linux-sunxi/commit/16b25a95327f45a995f6efcf3e9d83a414231af9.patch wget https://github.com/linux-sunxi/linux-sunxi/commit/dea62f21deb177053b84b15a519dff6c74d061d9.patch wget https://github.com/linux-sunxi/linux-sunxi/commit/d47d367036be38c5180632ec8a3ad169a4593a88.patch git am 5052b83aa44dc16d6662d8d9d936166c139ad8c5.patch git am 9a1cd034181af628d4145202289e1993c1687db6.patch git am c4c4664ed1a2f35e54a33ae4e65f517721ff43b5.patch git am ade08aa6e5249a9e75a97393e86c250b2bcb3ec8.patch git am 16b25a95327f45a995f6efcf3e9d83a414231af9.patch git am dea62f21deb177053b84b15a519dff6c74d061d9.patch git am d47d367036be38c5180632ec8a3ad169a4593a88.patch

ImportError: No module named _libfdt
If you see the following error when compiling on Arch Linux arm ImportError: No module named _libfdt

install dtc sudo pacman -S dtc

= Adding a new device to upstream U-Boot =

http://lists.denx.de/pipermail/u-boot/2014-December/199351.html

Failsafe DRAM settings, based on standard JEDEC timings
Each device has DRAM settings configured in its defconfig file in the U-Boot "configs" directory (here is an example for the Cubietruck board). The slow failsafe DRAM settings for an A10/A13/A20 device may look like:  +S:CONFIG_DRAM_CLK=360 +S:CONFIG_DRAM_ZQ=123 +S:CONFIG_DRAM_EMR1=4 +S:CONFIG_DRAM_TIMINGS_DDR3_800E_1066G_1333J=y

A more complete set of available Kconfig options and their descriptions can be found here: http://git.denx.de/?p=u-boot.git;a=blob;f=board/sunxi/Kconfig;h=e1d4ab148f0838d746889775cfbab5bed57838bf;hb=a705ebc81b7f91bbd0ef7c634284208342901149#l177

The settings from the Android firmware
Somewhat better settings can be retrieved by the meminfo tool from the stock Android or GNU/Linux system, provided by the device manufacturer. It still makes sense to test the reliability of the resulting DRAM configuration. Because some vendors are providing poor configuration for ZQ or EMR1, but nevertheless trying to optimistically set the DRAM clock speed too high.

Performance optimized DRAM settings
Tuning DRAM setting for each individual board can provide much better performance than the failsafe defaults. This involves trial and error testing of different settings using a tool until an optimal combination is found. The DRAM Controller page provides links to start researching this topic. This approach will be time consuming, so a satisfactory solution using one of the other approaches may be best to start with.

= See also =
 * Mainline Kernel Howto
 * Mainline U-Boot supported devices
 * U-Boot/Changelog