This directory provides a bootloader image that loads a Linux initramfs that exports common block devices (EMMC, NVMe) as USB mass storage devices using the Linux gadget-fs drivers.
This allows Raspberry Pi Imager to be run on the host computer and write OS images to the Raspberry Pi or Compute Module block devices.
To run load the USB MSD device drivers via RPIBOOT run
cd mass-storage-gadget64
../rpiboot -d .
The mass-storage-gadget image automatically enables a UART console for debugging (user root empty password).
Once secure-boot has been enable the OS boot.img file must be signed with the customer private key.
On Pi5 firmware must also be counter-signed with this key.
The sign.sh script wraps the command do this on Pi4 and Pi5.
KEY_FILE=$HOME/private.pem
./sign.sh ${KEY_FILE}WARNING: The signed images will not be bootable on a Pi5 without secure-boot enabled. Run ./reset.sh to reset the signed images to the default unsigned state.
The buildroot configuration and supporting patches is available on the mass-storage-gadget64 branch of the Raspberry Pi buildroot repo.
git clone --branch mass-storage-gadget64 [email protected]:raspberrypi/buildroot.git
cd buildroot
make raspberrypi64-mass-storage-gadget_defconfig
makeThe output is written to output/target/images/sdcard.img and can be copied to boot.img