DAS U BOOT HOW TO

The installation step will instruct how to install this on the installation media (e.g. When the build has completed, there will be u-boot-sunxi-with-spl.bin available in your u-boot tree. (When compiling natively, omit the CROSS_COMPILE=…) Make CROSS_COMPILE=aarch64-linux-gnu- B元1=/build/sun50i_a64/debug/bl31.bin Make CROSS_COMPILE=aarch64-linux-gnu- B元1=/build/sun50i_a64/debug/bl31.bin menuconfig Make CROSS_COMPILE=arm-linux-gnueabihf- menuconfigĪrm64 make CROSS_COMPILE=aarch64-linux-gnu- B元1=/build/sun50i_a64/debug/bl31.bin _defconfig Use menuconfing to play with the settings if you feel like it and then just build it:Īrmhf make CROSS_COMPILE=arm-linux-gnueabihf- _defconfig When you have determined what just configure U-Boot with a suitable default configuration. Make CROSS_COMPILE=aarch64-linux-gnu- PLAT= DEBUG=1 bl31 (See board/sunxi/README.sunxi64 in uboot sources for more infos.) PLAT=sun50i_a64 for example is suitable for H5 and A64 devices. In order to build U-Boot for a arm64 device you need to build Arm Trusted Firmware (ATF) as a prerequisite first. So, if your device is Cubieboard2 your build target is Cubieboard2_defconfig.

5.1 USB 1.x, USB keyboards (U-Boot _defconfig.

3.2 Setting u-boot environment variables.

GRUB Legacy is also divided in components that are called “stages”, but these are just internal divisions of GRUB that were created to work around legacy BIOS restrictions GRUB stages are not the same as the systems design first/second stage bootloader terminology. In the systems design sense, the entirety of GRUB would be a second-stage bootloader.

DAS U BOOT PC

In the systems design sense, on a legacy x86 PC with a goal of running Linux, the BIOS is the first-stage bootloader: it is arranged in ROM (or flash EEPROM) to be the first thing the processor will execute after a cold reset, and its job is to initialize the necessary hardware and load a relatively compact program from a fixed or otherwise well-defined location. It looks like you’re perhaps confusing the terminology that was specific to GRUB Legacy (first stage, second stage, stage 1.5) with more generic systems design terminology for boot loaders.

U-Boot is not a BIOS-compatible bootloader nor an easy drop-in replacement for BIOS when its documentation says it supports x86, it only means that U-Boot can readily be integrated with hardware projects that use an x86 processor on custom hardware. On PC hardware, this can be a bigger challenge than you expected, as chipset programming documentation may not be easily available for all PC chipsets. Of course, replacing the BIOS requires that your custom firmware must first be able to handle the initialization of your system’s chipset, and testing and enabling the RAM after a cold start.

DAS U BOOT CODE

Therefore, the first step in using U-Boot on a legacy x86 PC would be to replace the BIOS with your own custom firmware that includes the first stage of U-Boot.Īfter you’ve done that, the old BIOS boot conventions like loading a 446-byte boot code from block #0 of the first hard disk won’t apply any more, and U-Boot’s conventions will be used instead. Although U-Boot supports x86 hardware, it does not include support for x86 BIOS firmware.

Das u boot