Compiling AT91bootstrap 4.0.4

AT91bootstrap is the 2nd level bootloader used by the Microchip ARM MPUs to initializate the internal hardware (clocks, peripherals, DDR DRAM, etc) at startup and load the Linux Kernel image from the first microSD partition. This article illustrates how to compile at91bootstrap for the RoadRunner module

Toolchain installation

First of all you need to install the toolchain (cross compiler, linker, etc) on your Linux Ubuntu PC following this article (tested on Ubuntu 18.04.4 LTS):

Download the sources from Microchip GitHub repository

cd at91bootstrap-4.0.4

Download and apply the Acme patches

patch -p1 < acme.patch


make roadrunner_defconfig


make acqua_defconfig

Source compiling

To compile at91bootstrap type:

make CROSS_COMPILE=arm-linux-gnueabihf-

it will generate a binary file in build/binaries directory called __boot.bin_.

Copy boot.bin on a bootable MicroSD

Insert a microSD on your Linux PC and type:

cp build/binaries/boot.bin /media/$USER/boot

Be sure that PA30 (MMC1 CD) is wired on GND.

File used


Sergio Tanzilli
Systems designer, webmaster of and founder of Acme Systems srl

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