Build the boot script boot.scr / u-boot.scr

Some platforms require a U-Boot boot script (boot.scr or u-boot.scr) on the SD card BOOT partition to tell U-Boot how to load the kernel, device tree, and (optionally) the FPGA bitstream into memory. This page explains how to build that script from a plain-text source file using the mkimage tool.

Note

The boot script is not the same as BOOT.BIN. For AMD Xilinx Zynq/ZynqMP/Versal BOOT.BIN generation, see Build the boot image BOOT.BIN. For Intel boot images, see Generating HDL boot image for Intel projects.

Prerequisites

The mkimage utility is required. It is part of the u-boot-tools package on most Linux distributions:

~$

sudo apt-get install u-boot-tools

Verify the installation:

~$

mkimage -V

Boot script source files

We provide ready-made boot script source files (*.txt) for all Kuiper-supported carriers in the boot_txt_files repository, under the boot_txt_files/ directory.

The following source files are available:

Source file	Platform / carrier	Output file name
`zynq.txt`	Zynq (e.g. ZED, ZC706)	`boot.scr`
`zynqmp.txt`	Zynq UltraScale+ MPSoC (e.g. ZCU102)	`boot.scr`
`k26.txt`	Kria K26 SOM	`boot.scr`
`versal.txt`	Versal (e.g. VCK190)	`boot.scr`
`vpk180.txt`	Versal Premium (VPK180)	`boot.scr`
`cyclone5.txt`	Intel Cyclone V SoC (e.g. C5SoC)	`u-boot.scr`
`jupiter_sdr.txt`	Jupiter SDR	`boot.scr`
`no_bitfile_zynq.txt`	Zynq — without bitstream loading	`boot.scr`
`no_bitfile_de10nano.txt`	DE10-Nano — without bitstream loading	`u-boot.scr`

Download the source file that matches your platform:

~$

wget https://raw.githubusercontent.com/analogdevicesinc/wiki-scripts/main/boot_txt_files/<platform>.txt

Replace <platform> with one of the file names from the table above (e.g. zynqmp, versal, cyclone5).

Building the boot script

The mkimage command converts the plain-text source into a U-Boot script image. The general form is:

mkimage -A <arch> -O linux -T script -C none -a 0 -e 0 \
    -n "<description>" \
    -d <input>.txt <output>.scr

Where:

-A <arch> — target architecture (arm for 32-bit, arm64 for 64-bit)
-O linux — operating system
-T script — image type (boot script)
-C none — no compression
-a 0 -e 0 — load and entry addresses (unused for scripts, set to 0)
-n "<description>" — a human-readable description embedded in the image
-d <input>.txt — the boot script source file
<output>.scr — the output boot script image

For AMD Xilinx platforms

This applies to Zynq, Zynq UltraScale+ MPSoC, Kria K26, Versal, and VPK180 carriers. The output file is boot.scr.

~$

mkimage -A arm -O linux -T script -C none -a 0 -e 0 \
    -n "Boot script" \
    -d <platform>.txt boot.scr

For Intel platforms

This applies to Cyclone V SoC and DE10-Nano carriers. The output file is u-boot.scr.

~$

mkimage -A arm -O linux -T script -C none -a 0 -e 0 \
    -n "Boot script" \
    -d <platform>.txt u-boot.scr

Note

Intel Cyclone V SoC projects expect the file name u-boot.scr, not boot.scr.

After building, copy the resulting script file to the BOOT (FAT32) partition of the SD card.