Das U-Boot is documented in **The U-Boot Documentation**. This is the top level of the U-Boot’s documentation tree. U-Boot documentation, like the U-Boot itself, is very much a work in progress; that is especially true as we work to integrate our many scattered documents into a coherent whole.

- **User-oriented documentation:** The following manuals are written for users of the U-Boot - those who are trying to get it to work optimally on a given system. Topics include Build U-Boot, Learn about U-Boot, Use U-Boot, Booting from TPL/SPL, Device Firmware Upgrade (DFU), Environment Variables, Device Tree Overlays, Flat Image Tree (FIT), PXE Boot and extlinux.conf, Shell commands, Booting OS, and File Systems.

- **Build and development:** Build U-Boot covers Obtaining the source, Building with GCC, Building with Clang, Reproducible builds, GitLab CI / U-Boot runner container, Host tools, Buildman build tool, Building documentation, and Create build database for IDEs. The following manuals are written for developers of the U-Boot - those who want to contribute to U-Boot.

- **API and subsystem documentation:** These books get into the details of how specific U-Boot subsystems work from the point of view of a U-Boot developer. Topics include Boot Count Limit, Clock API, Device firmware update, Driver Model, UEFI subsystem, Events, File system API, Logging API, Partition API, Random number generation, Serial system, System reset, Test Framework, Timer Subsystem, and Unicode support.

- **Architecture and board documentation:** These books provide programming details about architecture-specific implementation, including ARC, ARM64, M68K / ColdFire, MIPS, RISC-V, Sandbox, x86, and Xtensa. Board-specific doc books provide details about board-specific information and are organized in a vendor subdirectory.

- **Android and Chromium OS:** Android-specific doc books provide information about booting the Android OS from U-Boot, manipulating Android images from U-Boot shell and discusses other Android-specific features available in U-Boot. Chromium OS-specific doc includes Chromium OS Support in U-Boot, Running U-Boot with Chromium OS verified boot, and Running U-Boot from coreboot on Chromebooks.

Please note that improvements to the documentation are welcome; join the U-Boot list at http://lists.denx.de if you want to help out.