Xilinx® FPGAs, system-on-chip (SoC) devices, and adaptive compute acceleration platforms (ACAPs) typically have multiple hardware and software binaries used to boot them to function as designed and expected. These binaries can include FPGA bitstreams, firmware images, bootloaders, operating systems, and user-chosen applications that can be loaded in both non-secure and secure methods.
Bootgen is a Xilinx tool that lets you stitch binary files together and generate device boot images. Bootgen defines multiple properties, attributes and parameters that are input while creating boot images for use in a Xilinx device.
The secure boot feature for Xilinx devices uses public and private key cryptographic algorithms. Bootgen provides assignment of specific destination memory addresses and alignment requirements for each partition. It also supports encryption and authentication, described in Using Encryption and Using Authentication. More advanced authentication flows and key management options are discussed in Using HSM Mode, where Bootgen can output intermediate hash files that can be signed offline using private keys to sign the authentication certificates included in the boot image. Bootgen assembles a boot image by adding header blocks to a list of partitions. Optionally, each partition can be encrypted and authenticated with Bootgen. The output is a single file that can be directly programmed into the boot flash memory of the system. Various input files can be generated by the tool to support authentication and encryption as well. See BIF Syntax and Supported File Types for more information.
Bootgen comes with both a GUI interface and a command line option. The tool is integrated into the Vitis™ Integrated Development Environment (IDE), for generating basic boot images using a GUI, but the majority of Bootgen options are command-line driven. Command line options can be scripted. The Bootgen tool is driven by a boot image format (BIF) configuration file, with a file extension of *.bif. Along with Xilinx SoC and ACAP, Bootgen has the ability to encrypt and authenticate partitions for Xilinx 7 series and later FPGAs, as described in FPGA Support. In addition to the supported command and attributes that define the behavior of a Boot Image, there are utilities that help you work with Bootgen. Bootgen code is now available on Github.