ESC + 2: Pressing the Escape key and the 2 key takes us to the U-Boot prompt ESC + 1: Pressing the Escape key and the 1 key takes us to the QEMU emulator We can switch between the emulator and the U-Boot console/prompt using a combination of keys Using the following bare minimum to start the emulationĪt this stage, we are presented with a QEMU virtual machine. We should now be left with a u-boot image, which we can now execute using QEMU. We now specify the required Cross Compiler and Architecture environment variables and before proceeding onto the make process config file later used to build the U-Boot image. Using ' make clean' ensures a clean build distribution and writes the required. With the above clue on hand, we can then further the search through examination of the MAINTAINERS file within the same directory, which leads us to the crown jewels, that is, the appropriate ' defconfig' file that we will use for our build. To gather our bearings, we can conduct a quick grep through the board directory to gather our bearings to find an appropriate configuration file. git archive as our preferred method:įor the purposes of our discussion and subsequent practical examples, we will choose to build U-Boot across an emulated environment that is using qemu-arm. This can be achieved in numerous ways, however, we like the cloning of the. To build U-Boot, the first requirement is to obtain the source code.
The name was cleverly chosen as a play on words based around the German submarine film ' Das Boot', which takes place in World War II on a German U-Boat. Later PPCBoot became U-Boot and was further widened to include x86 and MIPS architectures and by 2004 included support for 216 board manufacturers.įast-forwarding to the current day, U-Boot was renamed ' Das U-Boot' where ' Das' is the Germanic definitive article or simply ' The' translated into English. This collaboration saw the widening of the supported architectures. Further development saw a brief port of the bootloader to include ARM architecture through a project known as ARMBoot in 2002, with the end result being a merge back into PPCBoot in the same year. PPCBoot's initial release was July 19, 2000. Interestingly enough, the latter name, ' PPCBoot', was chosen somewhat based on the SourceForge restriction of digits being used in a project's name. In this guise, it was initially known as 8xxROM and was later renamed to PPCBoot. This open-source project first sprang into existence as a bootloader for the embedded PowerPC architecture. Running Das U-Boot in an emulator (QEMU) We will delve into the following Das U-Boot features, including: In this post, we will be describing the bootloader that goes by the name of Das U-Boot.
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