Raspberry Pi4 64 Bit Install

This page contains changes which are not marked for translation.

Warning
This page is in the process of being merged into the universal Raspberry Pi Install Guide

This wiki page explains how to install a 64bit Gentoo system on the Raspberry Pi 4.

Introduction

The install procedure of Gentoo on the Pi 4 is a standard Gentoo installation similar to the one described in the AMD64 Handbook but without a live medium: the storage (SD card or external SSD) that will be used by the Pi 4 needs to be setup on a separate Gentoo machine (whose platform is probably not aarch64)

Not tested

Analogue Video Output
Analogue Audio Output
Camera
Screen

Preparing the external storage

See also
Preparing the disks.

This section is obsoleted by the Raspberry Pi Install Guide ~~Minimally, the storage can be formatted with 2 partitions.~~

A fat32 formatted ESP /boot partition with the required firmware and kernel blobs. 512MB is sufficient.

An ext4 formatted / (root) partition for the system.
~~Assuming the target storage is mounted at /dev/sda, this can be written with:~~
root #fdisk /dev/sda
Welcome to fdisk (util-linux 2.38.1). Changes will remain in memory only, until you decide to write them. Be careful before using the write command.
~~To create the GPT label:~~
Command (m for help)g
Created a new GPT disklabel (GUID: E361F483-EDF0-5846-BDCE-5A92124726D9).
~~To create the first 1gb partition:~~
Command (m for help)n
Partition number (1-128, default 1): First sector (2048-124735454, default 2048):
Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-124735454, default 124733439): +1G
~~To create the root partition, spanning the rest of the volume:~~
Command (m for help)n
Partition number (2-128, default 2): First sector (2099200-124735454, default 2099200): Last sector, +/-sectors or +/-size{K,M,G,T,P} (2099200-124735454, default 124733439): Created a new partition 2 of type 'Linux filesystem' and of size 58.5 GiB.
~~The first partition's type can be set to ESP with:~~
Command (m for help)t
Partition number (1,2, default 2): 1 Partition type or alias (type L to list all): 1 Changed type of partition 'Linux filesystem' to 'EFI System'.
~~The staged partition table can be read with:~~
Command (m for help)p
Disk /dev/sdf: 59.48 GiB, 63864569856 bytes, 124735488 sectors Disk model: UHSII uSD Reader 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: gpt Disk identifier: E361F483-EDF0-5846-BDCE-5A92124726D9 Device Start End Sectors Size Type /dev/sdf1 2048 2099199 2097152 1G EFI System /dev/sdf2 2099200 124733439 122634240 58.5G Linux filesystem
~~If the partition table looks correct, it can be written with:~~
Command (m for help)w
The partition table has been altered. Calling ioctl() to re-read partition table. Syncing disks.
~~Once the partitions have been created, filesystems can be written with:~~
root #mkfs.fat /dev/sda1
root #mkfs.ext4 /dev/sda2

Mounting the base filesystem

In this guide, /dev/sda2 will be mounted to /mnt/gentoo.

root #mount /dev/sda2 /mnt/gentoo

Note
The boot partition will be mounted later, when needed.

Installing the Gentoo base system

See also
Installing a stage file.

From the target root directory, the stage3 file can be extracted with:

/mnt/gentoo #tar xvf stage3-arm64-<release timestamp>.tar.xz

QEMU user chroot

See also
Compiling with QEMU user chroot.

If the Gentoo machine being used to setup the Pi's storage device is not aarch64 (e.g. amd64), QEMU needs to be setup and configured to chroot into this environment:

Once configured, the user target can be copied with:

user $cp /usr/bin/qemu-aarch64 /mnt/gentoo/usr/bin

Then the chroot can be entered using sys-apps/arch-chroot:

root #arch-chroot /mnt/gentoo

Configuring Portage

See also
Installing the base system.

COMMON_FLAGS

Raspberry Pi 4B users should use the -mcpu=cortex-a72 compiler in favor of -march and -mtune altogether. march and mtune behavior on arm64 systems is different from amd64. Source

FILE /etc/portage/make.conf

COMMON_FLAGS="-mcpu=cortex-a72 -ftree-vectorize -O2 -pipe -fomit-frame-pointer"

Note
-ftree-vectorize and -fomit-frame-pointer allow utilization of more registers.

Warning
-mcpu=native could be used but may cause issues with distcc.

VIDEO_CARDS

The mesa drivers the Pi 4 needs to have full hardware acceleration are v3d and vc4

FILE /etc/portage/make.conf

VIDEO_CARDS="v3d vc4"

It also needs specific firmware, loaded in the section "BIOS" configuration

Raspberry Pi Firmware

The Raspberry Pi 4 second stage bootloader (bootcode.bin) is included on SPI flash and does not need to be added to the /boot (ESP) volume. ^[1]

The following files are not included on builtin device storage, and must be added to the ESP:

start4.elf
fixup4.dat

Important
/boot must be a fat32 formatted, ESP labeled partition to be bootable.

These files are part of sys-boot/raspberrypi-firmware, and are automatically installed to /boot on emerge:

root #emerge --ask sys-boot/raspberrypi-firmware

Tip
This package essentially just copies the official firmware files to the boot partition.

"BIOS" configuration: /boot/config.txt

The following options may be useful:

disable_overscan=1 Disable video overscanning.
dtoverlay=vc4-kms-v3d Enable GPU acceleration
kernel kernel8.img Change the path to the kernel file. The default for the RPi4 is kernel8.img.
cmdline=cmdline.txt Change the path to the cmdline.txt (kernel commandline) file.
initramfs init.gz followkernel Change the path to the loaded initramfs, followkernel should be used as it loads the image immediately after the kernel in memory.
arm_boost=1 Enable 1.8GHz frequency boost instead of 1.5Ghz.
dtparam=audio=on Enable audio output
dtparam=i2c_arm=on Enable I2C.
dtparam=spi=on Enable SPI

Tip
Any of these options can be written to /boot/config.txt.

See also
A full list of options is available in the official documentation.

There is a new alternative audio mode that does not use the audio=on dtparam.

Kernel command line: /boot/cmdline.txt

This file /boot/cmdline.txt contains the command line that is given to the kernel. One important information it needs to contain is where the root file system is.

FILE /boot/cmdline.txt

console=tty1 root=PARTUUID=[root-partition-uuid] fsck.repair=yes rootwait

or

FILE /boot/cmdline.txt

console=tty1 root=UUID=[root-filesystem-uuid] fsck.repair=yes rootwait

Important
root=UUID=[root-filesystem-uuid] requires an initrd to provide the userspace mount command.

Kernel

The kernel can either be manually compiled and fully customized or the official binary kernel from Raspberry can be installed.

Important
Make sure the kernel blob filename in /boot is referenced correctly in /boot/config.txt

Raspberry official binary kernel

Install sys-kernel/raspberrypi-image and sys-kernel/raspberrypi-sources

root #emerge --ask sys-kernel/raspberrypi-image sys-kernel/raspberrypi-sources

Manual build

If building in a chroot:

/usr/src/linux #make bcm2711_defconfig

To cross compile the kernel:

root #ARCH=arm64 CROSS_COMPILE=aarch64-unknown-linux-gnu- make bcm2711_defconfig

Check the other kernel configuration settings given in configure the kernel.

Kernel config tweaks

Setting the default CPU governor

The default CPU governor (CPU_FREQ_DEFAULT_GOV) is powersave. This runs the CPU at 600MHz all the time. CPU governors can be controlled in /proc or the default CPU governor can be changed to be schedutil or ondemand:

KERNEL Set the default CPU governor

    CPU Power Management  --->
        CPU Frequency scaling  --->
            [*] CPU Frequency scaling
                Default CPUFreq governor (schedutil) --->
            <*> 'schedutil' cpufreq policy governor

Building the kernel

To build in a chroot:

/usr/src/linux #make -j<threads>

To cross compile:

/usr/src/linux #ARCH=arm64 CROSS_COMPILE=aarch64-unknown-linux-gnu- make -j<threads>

Installing the kernel

Warning
make dtbs_install does not install DTBs and overlays to the correct directory.

The kernel can be installed to /boot with:

/usr/src/linux #make dtbs_install

Kernel modules can be installed with:

/usr/src/linux #make -j<threads> modules_install

Installing Device Tree Files and Overlays

Compiled DTBs are stored in arch/arm64/boot/dts/. bcm2711-rpi-4-b.dtb is required for the RPI4:

root #

mkdir --parents /boot/overlays

root #

cp -vR arch/arm64/boot/dts/overlays/*.dtbo /boot/overlays

root #cp -v arch/arm64/boot/dts/broadcom/bcm2711-rpi-4-b.dtb /boot

Note
DTBs may change between kernel updates, remember to use versions with the appropriate kernel.

Tip
The Pi 400 uses arch/arm64/boot/dts/broadcom/bcm2711-rpi-400.dtb.

Configuring the system

The AMD64 handbook can be followed starting Configuring the system until the end, except for Configuring the bootloader which is taken care of in #Firmware / Boot partition section. Then, the storage can be safely unmounted and plugged in the Pi 4 and have it successfully booting and working as expected.

Zram

SWAP space was intentionally not allocated to the SD card, because it can destroy SD cards without wear-leveling. To use compressed RAM for swap space, as well as /var/log:

FILE /etc/conf.d/zram-init

# zram settings...
# SPDX-License-Identifier: GPL-2.0-only

# load zram kernel module on start?
load_on_start=yes

# unload zram kernel module on stop?
unload_on_stop=yes

# Number of devices.
# This value is also passed to the kernel module on modprobe.
num_devices=4
# swap - 500M (or a fourth of available memory if uncommenting)
type0=swap
flag0= # The default "16383" is fine for us
size0=512
#size0=`LC_ALL=C free -m | awk '/^Mem:/{print int($2/4)}'`
maxs0=1 # maximum number of parallel processes for this device
algo0=zstd # zstd (since linux-4.18), lz4 (since linux-3.15), or lzo.
labl0=zram_swap # the label name

# /var/log - 1G
type1=/var/log
size1=1024
opts1=relatime # e.g. "noatime" or "strictatime" are also reasonable choices
mode1=1755
maxs1=1
algo1=zstd
labl1=var_log_dir

# /var/lib/dhcpcd/ - 1m
type2=/var/lib/dhcpcd
size2=1
opts2=relatime # e.g. "noatime" or "strictatime" are also reasonable choices
mode2=1755
maxs2=1
algo2=zstd
labl2=dhcpcd_dir

# /var/lib/chrony/ - 1m
type3=/var/lib/chrony
size3=1
opts3=relatime # e.g. "noatime" or "strictatime" are also reasonable choices
mode3=1755
owgr3=123:123
maxs3=1
algo3=zstd
labl3=chrony_dir

Note
If using a 1GB model, a smaller /var/log should be used.

Tip
Remember to increment device numbers when adding devices, and change num_devices.

Then zram-init can be added to the boot runlevel:

root #rc-update add zram-init boot

Removing unnecessary cron jobs

Unnecessary writing can kill SD cards, logging to memory or remotely and disabling unneeded periodic tasks can extend the life of a Raspberry Pi's root file system device.

Disabling the man-db daily cron job

By default, sys-apps/man-db installs /etc/cron.daily/man-db which updates man cache files daily. This action is only necessary when new man pages are added, and can be removed by masking that file from being installed, and deleting it moving it to another runlevel.

Masking the cron job file

Important
These changes will not persist if sys-apps/man-db is updated.

FILE /etc/portage/make.confEnsure portage does not reinstall that file to /etc/cron.daily

INSTALL_MASK="/etc/cron.daily/man-db"

Disabling the daily cron task

The cron task can be removed or moved to a less frequent cron job:

root #mv /etc/cron.daily/man-db /etc/cron.monthly/man-db

or:

root #chmod -x /etc/cron.daily/man-db

Manually updating the cache

The man page cache can be manually updated with:

root #mandb

Tip
This should be run when packages are updated.

Making the DUID static

By default, dhcpcd will generate a randomized DUID when it first runs. To change this to be derived from the interface MAC address, so it can be safely stored in RAM:

FILE /etc/dhcpcd.confMake DUID based on MAC

duid ll

Misc

WiFi

WiFi needs three firmware files in /lib/firmware/brcm/. These are now provided by sys-kernel/linux-firmware

brcmfmac43455-sdio.bin
brcmfmac43455-sdio.clm_blob
brcmfmac43455-sdio.txt

~~Which is almost but not quite the same as the Pi3. The catch is in brcmfmac43455-sdio.txt where grep boardflags3 produces different results for the Pi3 and Pi4 files.~~
~~The Pi4 version returns boardflags3=0x44200100 The Pi3 version returns boardflags3=0x48200100~~
With the wrong brcmfmac43455-sdio.txt file, bluetooth will work but not WiFi.
These files, including the Pi 4 version of above file, are found in sys-firmware/raspberrypi-wifi-ucode, to install it you'll also need to install sys-kernel/linux-firmware with the savedconfig USE flag and remove the conflicting files from the saved configuration, and then re-emerge linux-firmware to apply the new de-conflicted saved configuration:

/lib/firmware/brcm/brcmfmac43430-sdio.bin
/lib/firmware/brcm/brcmfmac43430-sdio.txt
/lib/firmware/brcm/brcmfmac43436-sdio.bin
/lib/firmware/brcm/brcmfmac43436-sdio.clm_blob
/lib/firmware/brcm/brcmfmac43436-sdio.txt
/lib/firmware/brcm/brcmfmac43455-sdio.bin
/lib/firmware/brcm/brcmfmac43455-sdio.clm_blob
/lib/firmware/brcm/brcmfmac43455-sdio.txt
/lib/firmware/brcm/brcmfmac43456-sdio.bin
/lib/firmware/brcm/brcmfmac43456-sdio.clm_blob
/lib/firmware/brcm/brcmfmac43456-sdio.txt

EEProm updates

dev-embedded/rpi-eeprom provides the eeprom files and the updater, as well as a service to check and apply the updates.

There are 3 release channels of firmware updates:

critical - Default - rarely updated
stable - Updated when new/advanced features have been successfully beta tested.
beta - New or experimental features are tested here first.

To configure which release channel you'd like the updater service to follow, edit /etc/conf.d/rpi-eeprom-update.

Power over Ethernet

The Pi3b PoE HAT will power the P4 and a USB SSD.

Fan control works.

microSD trim/discard

The microSD interface supports the trim command:

Pi4_~arm64 ~ #fstrim -av


 /boot: 7.7 GiB (8250073088 bytes) trimmed on /dev/mmcblk0p1

If you have a suitable microSD card, consider adding fstrim to a weekly or monthly cron job.

USB attached SSD

Users with USB3 attached SSDs may have noticed that trim is not supported. It is a feature of USB storage that trim is disabled by default. Trim can be enabled with mixed success. Only USB3 is supported and the USB3 to SSD bridge device must be able to pass the trim command.

One other thing to note, the Raspberry pi currently only supports booting from usb mass storage devices (including external hard drives) that have a 512 byte logical sector size. You may need to reformat (with the drive manufacturer's utility) them to enable 512 byte emulation.

Cross-compiling

Cross-compiling is by far the fastest way to create packages for aarch64. Afterwards, binhost can be set up to download the packages that you desire. It is possible to create the entire RPI4 by using cross-compile and creating it through a stage2. Distcc is also another great method for compiling aarch64 code. Code can be offloaded onto the main computer. Distcc will have more difficulties in boostraping though, unlike Cross-compiling.

Acknowledgements

NeddySeagoon for taking over maintenance and upstreaming many ebuilds from sakaki's overlay after sakaki's retirement ( Neddy's fork )

sakaki's topic on the Raspberry Pi forums

All the contributors to issue 3032 on the Raspberry Pi GitHub repository.

↑ https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#raspberry-pi-4-and-raspberry-pi-5-boot-flow

[1] ttps://www.raspberrypi.com/documentation/computers/raspberry-pi.html#raspberry-pi-4-and-raspberry-pi-5-boot-flow

[1]