Contents

  1. Current status (2024-07)
    1. Pulse Audio and Sound don't work as of 2021-04-07
  2. Boot and Installing Debian on the Raspberry PI 4
    1. Tested and Daily Debian Images
    2. Using EFI Firmware and the regular Debian Installer
    3. Booting from USB
    4. Bootloaders Alternatives
      1. Directly load kernel and initramfs from RPI firmware
      2. RPI firmware loads u-boot, which loads kernel/initramfs
      3. RPI firmware loads u-boot, which loads grub using EFI, which loads kernel/initramfs
      4. Tianocore EDK II on RPI4 is used to boot iPXE as a Network Boot/Installer for Debian
      5. Tianocore EDK II on RPI4 is used to boot Debian
      6. Network boot
      7. U-boot
  3. Hardware Information and Issues
  4. Upstream kernel
  5. Various technical tips
    1. changing command line
    2. changing kernel version to boot
    3. serial console
    4. Root file system on a USB disk
    5. USB 3 enclosures
    6. Bluetooth
    7. Build a kernel as a Debian package
      1. Building a custom kernel from upstream (mainline) sources
      2. Building a custom kernel from github.com/raspberrypi/linux sources
    8. Accelerated 3D graphics on Debian
    9. GPIO support
      1. using RPi.GPIO (python3-rpi.gpio)
      2. using GPIOZERO

This page provides details about Raspberry Pi 4. You probably want to read the RaspberryPi page first (and maybe look at the images available at https://raspi.debian.net/), and then decide whether you want to read this page.

Current status (2024-07)

Pulse Audio and Sound don't work as of 2021-04-07

You won't get sound using pulse audio using and the current debian installs using HDMI or A/V.

Boot and Installing Debian on the Raspberry PI 4

Tested and Daily Debian Images

We are automatically building daily images to run on all of the Raspberry Pi models, including the Raspberry Pi 4. There are also Tested Images that are verified to work and have their issues documented.

This is currently the recommended way of using Debian on the Raspberry Pi 4

Using EFI Firmware and the regular Debian Installer

The Pi Firmware Task Force works on an SBBR-compliant (UEFI+ACPI) AArch64 firmware for the Raspberry Pi 4 which allows the normal, vanilla Debian aarch64 installer to run and install a working Debian bullseye on the Raspberry PI.

Instructions to doing so are here and here.

The installed system does not use the Device Tree approach that is common on the ARM platforms to detect and enumerate hardware. Instead, vanilla ACPI is used like this is the case on the normal PC/Intel architecture. This might cause Raspberry Pi device drivers to support ACPI which some of today's device drivers (2021-06) don't do. If hardware that works on a device tree system doesn't work on an EFI/ACPI system, it might be possible that the device driver doesn't support ACPI yet. Unfortunately, the most prominent driver suffering from this lack of ACPI support is vc4, making this installation method unsuitable for systems that need a graphical console.

As of 2024-7, The EFI firmware limits the usable memory amount to 3 GB to cater for a hardware issue that has been worked around in the Debian 11 and 12 kernel. The option to enable the full memory is accessible in the EFI Setup at system startup: Device Manager → Raspberry Pi Configuration → Advanced Configuration and set Limit RAM to 3 GB to <Disabled>. This setting is safe for those kernels.

Booting from USB

Earlier versions of the Raspberry Pi 4 can only boot from the Micro SD card. Since April 2020, a boot loader EEPROM that can also boot from USB storage and UASP media is used. The EEPROM can be updated with media from here.

Bootloaders Alternatives

There are several ways to boot a kernel on the Debian 11 and 12 kernel

Directly load kernel and initramfs from RPI firmware

That's what the Debian images currently do.

RPI firmware loads u-boot, which loads kernel/initramfs

That's what the Ubuntu images do, and is promising.

FixMe 

# https://a-delacruz.github.io/ubuntu/rpi3-setup-64bit-uboot.html
# mkimage -A arm64 -O linux -T script -d boot.txt boot.scr
# vmlinuz and initrd must be converted. See https://linux-sunxi.org/Initial_Ramdisk or https://andrei.gherzan.ro/linux/uboot-on-rpi/
#   mkimage -A arm64 -T ramdisk -C none -n uInitrd -d initrd.img uInitrd
#   mkimage -A arm -O linux -T kernel -C none -a 0x00008000 -e 0x00008000 -n "Linux kernel" -d vmlinuz uImage
#setenv bootargs earlyprintk console=ttyS0,115200 console=tty1 root=LABEL=writable rw
#fdt addr ${fdt_addr} && fdt get value bootargs /chosen bootargs

RPI firmware loads u-boot, which loads grub using EFI, which loads kernel/initramfs

That's what OpenSUSE does. See https://www.suse.com/media/article/UEFI_on_Top_of_U-Boot.pdf on archive.org

Tianocore EDK II on RPI4 is used to boot iPXE as a Network Boot/Installer for Debian

This method provides a UEFI Network boot environment with a user GUI. SD Card or USB is not required. Requirements:

Tianocore EDK II on RPI4 is used to boot Debian

This method provides a UEFI boot environment on the SD card with a user GUI.

Network boot

Some info at http://lig-membres.imag.fr/duble/software/raspberry-pi-netboot/

U-boot

Hardware Information and Issues

Upstream kernel

Various technical tips

changing command line

At least in bullseye, raspi-firmware overwrites /boot/firmware/cmdline.txt . This is done on every call of update-initramfs. There is a config file /etc/default/raspi-firmware to adjust the behavior. Extra command line options should go into /etc/default/raspi-extra-cmdline .

changing kernel version to boot

On the VFAT partition, change the entries in config.txt to the kernel and initramfs version.

E.g., 

kernel=vmlinuz-5.16.0-6-arm64
initramfs initrd.img-5.16.0-6-arm64

serial console

https://www.raspberrypi.org/documentation/usage/gpio/

Red

+5V

Green

Tx

White

Rx

Black

GND

Black

GND

White

TXD

GPIO 14

Green

RXD

GPIO 15

add enable_uart=1 to /boot/config.txt then connect to the serial port of your client system:

On a Raspberry Pi 4B 4G with bullseye/linux 5.10.13-1, the serial stopped working after the vc4 module was loaded. As a workaround, add module_blacklist=vc4 to the command line to make it work

Root file system on a USB disk

As of bullseye/linux 5.10.13-1, the xhci/USB3 controller is not initialized until the reset_raspberrypi is loaded. This is by default not included in the initramdisk, making it impossible to use a usb disk as root filesystem. To make it work create an updated initramdisk by booting the Raspberry Pi from a MicroSD card or via network with the same kernel. Add reset_raspberrypi to /etc/initramfs-tools/modules of the running file system and run update-initramfs -k all -u (977694) Then copy the new /boot/initrd.img-{kernel}-amd64 to same location on your USB disk.

(Editor's Note 2021-06: This does not seem to be case for EFI installs in as long as the flashed bootloader is current)

USB 3 enclosures

Many USB3 enclosures (especially with jmicron chip) do not work with uas. To make them work find out the device/vendor id with lsusb and add usb-storage.quirks=152d:9561:u to your kernel command line (replace 152d:9561 with your device/vendor id).

Bluetooth

needs some firmware: 

wget -O /lib/firmware/brcm/BCM4345C5.hcd https://github.com/armbian/firmware/raw/master/brcm/BCM4345C5.hcd
wget -O /lib/firmware/brcm/BCM4345C0.hcd https://github.com/armbian/firmware/raw/master/BCM4345C0.hcd

Build a kernel as a Debian package

See BuildADebianKernelPackage

To disable DEBUG_INFO before build: scripts/config --disable DEBUG_INFO

https://stackoverflow.com/questions/7505164/how-do-you-non-interactively-turn-on-features-in-a-linux-kernel-config-file/39440863#39440863

With some boot methods, vmlinuz must be decompressed in /boot/firmware, or RPI4 won't boot. (zcat vmlinuz-... > vmlinux-... ; then point config.txt to vmlinuz)

Building a custom kernel from upstream (mainline) sources

# disable debug info
scripts/config --disable DEBUG_INFO
# build uncompressed kernel
sed -i '/KBUILD_IMAGE/ s/.gz//' arch/arm64/Makefile
# build debs
make -j `nproc` bindeb-pkg

Building a custom kernel from github.com/raspberrypi/linux sources

# generate config
make bcm2711_defconfig
# disable debug info
scripts/config --disable DEBUG_INFO
# build uncompressed kernel
sed -i '/KBUILD_IMAGE/ s/.gz//' arch/arm64/Makefile
# build debs
make -j `nproc` bindeb-pkg

Then copy and install the generated deb.

After installing:

Example config.txt: 

[pi4]
enable_uart=1
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
#dtoverlay=vc4-fkms-v3d
max_framebuffers=2
arm_64bit=1
kernel=vmlinuz

(You don't need an initrd)

Example cmdline.txt: 

console=tty1 console=ttyS0,115200 root=/dev/mmcblk0p2 rw elevator=deadline fsck.repair=yes net.ifnames=0  rootwait

Accelerated 3D graphics on Debian

To get accelerated 3D graphics on Debian, you will need the following (status on 2021-02):

Example config.txt: 

arm_64bit=1
enable_uart=1
upstream_kernel=1
#http://lists.infradead.org/pipermail/linux-rpi-kernel/2020-November/007906.html
disable_fw_kms_setup=1

kernel=vmlinuz
initramfs initrd.img

Example cmdline.txt: 

console=tty0 console=ttyS1,115200 root=/dev/mmcblk1p2 rw fsck.repair=yes net.ifnames=0  rootwait

(Editor's Note 2021-06: Is a running glxgears and present /sys/class/drm/card0 a sure sign of 3D acceleration working?)

GPIO support

All examples below are based on the "blinking led" schema. See https://pimylifeup.com/raspberry-pi-gpio/

The Debian kernel is compiled with CONFIG_STRICT_DEVMEM=y. You need to add iomem=relaxed to the kernel command line (/boot/firmware/cmdline.txt) to allow mmap on /dev/mem.

using RPi.GPIO (python3-rpi.gpio)

RPi.GPIO doesn't support the RPI 4 currently. See this bug https://sourceforge.net/p/raspberry-gpio-python/tickets/191/ (with a patch that makes it working).

Debian bug: 976114

using GPIOZERO

Debian has gpiozero version 1.4.1, which doesn't work with the RPI 4. After fixing RPi.GPIO, gpiozero 1.5.1 (current git) works.

Debian bug: 976118