(coreboot file system) Cramfs ext2 ext3 ext4 FAT FDOS JFFS2 ReiserFS Squashfs UBIFS ZFS Device tree Device tree is a data structure for describing hardware layout. Using Device tree, a vendor might be able to use a less modified mainline U-Boot on otherwise special purpose hardware. As also adopted by the Linux kernel, Device tree is intended to ameliorate the situation in the embedded industry, where a vast number of product specific forks (of U-Boot and Linux) exist. The ability to run mainline software practically gives customers indemnity against lack of vendor updates. History The project's origin is a 8xx PowerPC bootloader called 8xxROM written by Magnus Damm. In October 1999 Wolfgang Denk moved the project to SourceForge.net and renamed it to PPCBoot, because SF.net did not allow project names starting with digits. Version 0.4.1 of PPCBoot was first publicly released July 19, 2000. In 2002 a previous version of the source code was briefly forked into a product called ARMBoot, but was merged back into the PPCBoot project shortly thereafter. On October 31, 2002 PPCBoot−2.0.0 was released. This marked the last release under the PPCBoot name, as it was renamed to reflect its ability to work on other architectures besides the PPC ISA. PPCBoot−2.0.0 became U−Boot−0.1.0 in November 2002, expanded to work on the x86 processor architecture. Additional architecture capabilities were added in the following months: MIPS32 in March 2003, MIPS64 in April, Nios II in October, ColdFire in December, and MicroBlaze in April 2004. The May 2004 release of U-Boot-1.1.2 worked on the products of 216 board manufacturers across the various architectures. The current name Das U-Boot adds a German definite article, to create a bilingual pun on the classic 1981 German submarine film Das Boot, which takes place on a World War II German U-boat. It is free software released under the terms of the GNU General Public License. It can be built on an x86 PC for any of its intended architectures using a cross development GNU toolchain, for example crosstool, the Embedded Linux Development Kit (ELDK) or OSELAS.Toolchain. The importance of U-Boot in embedded Linux systems is quite succinctly stated in the book Building Embedded Linux Systems, by Karim Yaghmour, whose text about U-Boot begins, "Though there are quite a few other bootloaders, 'Das U-Boot', the universal bootloader, is arguably the richest, most flexible, and most actively developed open source bootloader available." Usages The ARM-based