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, and then decide whether you want to read this page.

Current status (2021-06)

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.

2021-06, the EFI firmware limits the usable memory amount to 3 GB to cater for a hardware issue that has been worked around in the recent kernels that Debian ships in bullseye and buster-backports. 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.

Boot Methods

There are several ways to boot...

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.


# mkimage -A arm64 -O linux -T script -d boot.txt boot.scr
# vmlinuz and initrd must be converted. See or
#   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 on

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


Hardware Information and Issues

Raspberry PI 4 8G

Upstream kernel

Other distros

Raspberry Pi OS (former Raspbian)



Alpine Linux

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.


initramfs initrd.img-5.16.0-6-arm64

loop-mounting images

# fdisk -l 2020-02-13-raspbian-buster-lite.img
Disk 2020-02-13-raspbian-buster-lite.img: 1,7 GiB, 1849688064 bytes, 3612672 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x738a4d67

Device                               Boot  Start     End Sectors  Size Id Type
2020-02-13-raspbian-buster-lite.img1        8192  532479  524288  256M  c W95 FAT32 (LBA)
2020-02-13-raspbian-buster-lite.img2      532480 3612671 3080192  1,5G 83 Linux

# mount -o loop,offset=$((8192*512)) 2020-02-13-raspbian-buster-lite.img mountpoint

serial console

















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

monitor DHCP traffic using tcpdump

tcpdump -i eth0 -pvn port 67 and port 68

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).


needs some firmware:

wget -O /lib/firmware/brcm/BCM4345C5.hcd
wget -O /lib/firmware/brcm/BCM4345C0.hcd

Build a kernel as a Debian package

See BuildADebianKernelPackage

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

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 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:

# Enable DRM VC4 V3D driver on top of the dispmanx display stack

(You don't need an initrd)

Example cmdline.txt:

console=tty1 console=ttyS0,115200 root=/dev/mmcblk0p2 rw elevator=deadline 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:


initramfs initrd.img

Example cmdline.txt:

console=tty0 console=ttyS1,115200 root=/dev/mmcblk1p2 rw 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

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 (with a patch that makes it working).

Debian bug: 976114


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