Raspberry Pi: Difference between revisions

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{{warning | 11 Feb 2021 - There is currently a known bug upstream <br />[https://github.com/raspberrypi/firmware/issues/1529 kernel/initramfs cannot be loaded from subdirectory with same name as volume label] }}
{{TOC right}}
 
This page explains how to install and use Alpine Linux on Raspberry Pi.
 
For scenarios where there is not expected to be significant changes to disk after setup (like running a static HTTP server), [[Diskless Mode|diskless mode]] is preferable, as running the entire system from memory will improve performance (by avoiding the slow SD card) and improve the SD card life (by reducing the writes to the card, as all logging will happen in RAM). Use [[Alpine local backup|Alpine Local Backup (lbu)]] utility to install packages, save local files, and tune the system.
 
[[Classic install or sys mode on Raspberry Pi|sys-mode installation]] is more appropriate for the following use cases:
 
* There will be constant changes to the disk after initial setup (for example, if you expect people to login and save files to their home directories)
* Logs should persists across reboots
* Plan to install packages which consume more space than can be loaded into RAM
* Plan to install kernel modules (such as ZFS)
 
sys-mode with [[OverlayFS#Immutable_root_with_tmpfs_overlay|Immutable root option]] can also be a solution to keep whole system on read-only media (lower RAM requirement than diskless mode which loads whole system in RAM) while avoiding SD wear as runtime files are mapped to ''tmpfs'' in RAM (check limitations).
 
== Compatibility list ==
 
Refer to the information regarding Raspberry Pi models in the below table when choosing image/file to download from [https://alpinelinux.org/downloads/ Downloads] page for your device. [[Installation#Verifying_downloaded_image|Verify]] the downloaded image before proceeding further.
{{:Include:Architecture support matrix}}
 
== Preparing for the installation==


{{TOC right}}
Irrespective of the Install media size, the fat partition size created when using the disk image is around 100Mb. If you need a bigger partition (highly recommended for diskless), proceed to download the tarball and follow the [[#Manual method|Manual method]].


This tutorial will help you install Alpine Linux on your Raspberry Pi.
=== Raspberry Pi Imager ===


== Preparation ==
[https://www.raspberrypi.com/news/raspberry-pi-imager-imaging-utility/ Raspberry Pi Imager] is an utility for writing a disk image file to a micro-SD card to be used as install media. When using the above utility, there is neither a need to download the image nor partition and format the media. This utility is available on Linux/macOS/Windows.


# [http://alpinelinux.org/downloads/ Download] the Alpine for Raspberry Pi tarball. You should be safe using the '''armhf''' build on all versions of Raspberry Pi (including Pi Zero and Compute Modules); but it may perform less optimally on recent versions of Raspberry Pi. The '''armv7''' build is compatible with Raspberry Pi 2 Model B. The '''aarch64''' build should be compatible with Raspberry Pi 2 Model v1.2, Raspberry Pi 3 and Compute Module 3, and Raspberry Pi 4 model B.
In Alpine linux, [[Install]] the {{pkg|rpi-imager}} package for the Raspberry Pi Imager utility. Follow the prompts and install media will be generated with few clicks. To launch the utility in graphical mode issue the command: {{Cmd|rpi-imager}}
# [[Create a Bootable USB#Format USB stick|Create a bootable FAT32 partition on your SD card.]] The partition type should be <code>W95 FAT32 (LBA)</code>. (The current type can be found in the "Type" column in the output of <code>fdisk -l</code>.) You can use a partitioning tool such as [https://en.wikipedia.org/wiki/GNOME_Disks gnome-disks] or [http://linux.die.net/man/8/fdisk fdisk].
# Create a filesystem on the partition with <code>mkdosfs -F 32 /dev/sdX1</code> (Replace sdX1 with the correct reference to the partition you just created.)
# Mount the partition and extract the tarball contents onto it.


Optionally create a '''usercfg.txt''' file on the partition to configure low-level system settings. Specifications can be found [https://www.raspberrypi.org/documentation/configuration/config-txt here]. However, note some settings can only be set directly in '''config.txt''', which may be overwritten after updates. In particular, <code>gpu_mem</code> will have no effect when specified in '''usercfg.txt''' ([https://github.com/raspberrypi/firmware/issues/1332 source]). Some interesting values include:
'''--cli''' option is also available. For complete usage guide, check out the <code>rpi-imager(1)</code> manpages, which you can [[install]] with the {{Pkg|rpi-imager-doc}} package.
* To enable audio: <code>dtparam=audio=on</code>
* If you see black edges around your screen after booting the Pi, you can add <code>disable_overscan=1</code>


Recent versions include Broadcom firmware files. If you're using an older Alpine version, see [[#Wireless_support_with_older_Alpine_images|section below]].
Proceed to [[#Installation|Installation]], if no further [[#Customize config.txt|customization]] is required.


== Installation ==
=== Manual method ===  


Alpine Linux will be installed in [[Installation#Installation_Handbook|diskless mode]], hence you need to use [[Alpine local backup|Alpine Local Backup (lbu)]] to save your modifications between reboots.
Alternatively, image or tarball may be downloaded, and SD card media formatted and prepared as per below:
* [https://alpinelinux.org/downloads/ Download] the Alpine Linux image or tarball for Raspberry Pi . Use the compability list above when choosing image/tarball to download.
* [[Create_a_Bootable_Device#Manually_copying_Alpine_files|Create a bootable FAT32 partition on your SD card.]] The partitioning and formatting part of the instructions on the linked page could be done using a graphical partitioning tool such as [https://en.wikipedia.org/wiki/GNOME_Disks gnome-disks], just make sure the partition type is <code>W95 FAT32 (LBA)</code>. (The current type can be found in the "Type" column in the output of <code>fdisk -l</code>.)
*: {{Tip|to reduce SD wear risk, it is advised to keep at least 10% of capacity as unallocated space. If media was previously partitioned at full capacity, running <code>blkdiscard /dev/mmcblk0</code> makes sure to [https://man7.org/linux/man-pages/man8/blkdiscard.8.html discard device sectors] before re-partitioning.}}
*: {{warning|Do not use the volume label <code>boot</code> for the fat32 partition. Due to an upstream [https://github.com/raspberrypi/firmware/issues/1529 bug], kernel/initramfs cannot be loaded from subdirectory with same name as volume label. Since kernel is installed to <code>boot/</code> folder in Alpine Linux, do not use the volume label <code>boot</code> for the fat32 partition.}}
* Extract the tarball to the root of the bootable FAT32 partition.


For users who will be using their Raspberry Pi in scenarios where there is not expected to be significant changes to disk after setup (like running a static HTTP server), this is likely preferable, as running the entire system from memory will improve performance (by avoiding the slow SD card) and improve the SD card life (by reducing the writes to the card, as all logging will happen in RAM). Diskless installations still allow you to install packages, save local files, and tune the system to your needs.  
== Customize config.txt ==


However, if you:
Instead of the BIOS found on a conventional PC, Raspberry Pi devices use a configuration file called '''config.txt'''. The GPU reads config.txt before the Arm CPU and Linux initialise.
* Expect there will be constant changes to the disk after initial setup (for example, if you expect people to login and save files to their home directories)
It is recommended to create a '''usercfg.txt''' file on boot partition to configure low-level system settings, as '''config.txt''' may be replaced during bootloader/system upgrades. Settings details can be found [https://www.raspberrypi.com/documentation/computers/config_txt.html here]. However, some [https://www.raspberrypi.com/documentation/computers/config_txt.html#include settings] can only be set in '''config.txt''', and will have no effect when specified in '''usercfg.txt''' (e.g. <code>gpu_mem</code>).
* Need logs to persist after reboot
Some interesting values include:{{Cat|usercfg.txt|<nowiki>enable_uart=1 # To enable the UART console:
* Plan to install packages which consume more space than can be loaded into RAM
dtparam=audio=on # To enable audio </nowiki>}}
* Want to install kernel modules (such as ZFS or Wireguard)
* By default system will use legacy video driver: some [https://www.raspberrypi.com/documentation/computers/legacy_config_txt.html#legacy-video-options options] may be used to adjust displays modes (e.g. if you see black edges around your screen after booting the Pi, you can add <code>disable_overscan=1</code>). Alternatively Linux DRM-KMS driver may be used (see below).
* If you plan to install on a Pi Computer Module 4 with I/O board, you may need to add: <code>otg_mode=1</code>
* Pi Zeros/A/A+/3A+/4B/400/5/500/CMs may be configured as USB serial-gadget (i.e. console access for setup) or ethernet-gadget networking: add <code>dtoverlay=dwc2,dr_mode=peripheral</code> in '''usercfg.txt''' and <code>modules=g_cdc</code> in '''cmdline.txt'''
* To maximize available CPU memory if not requiring extra GPU features (i.e. headless/CLI use-cases), cut-down bootloader may be installed with {{Pkg|raspberrypi-bootloader-cutdown|arch=}} package, and activated by adding <code>gpu_mem=16</code> in '''config.txt''' (setting may be wiped after bootloader package update).


Then you may be better served by a [[Classic install or sys mode on Raspberry Pi|sys-mode installation]].
== Installation ==
{{Seealso|Classic install or sys mode on Raspberry Pi}}


Follow these steps to install Alpine Linux in Diskless Mode:
{{Tip|To install Alpine Linux on a pi without keyboard, mouse & display, additional preparatory steps are available at [[Installation on a headless host|headless Installation]] page.}}


Follow these steps to install Alpine Linux in [[Diskless Mode]]:
# Insert the SD card into the Raspberry Pi and power it on
# Insert the SD card into the Raspberry Pi and power it on
# Login into the Alpine system as root.  Leave the password empty.
# Login into the Alpine system as root.  Leave the password empty.
# Check the current date and time by issuing <code>date</code>. Correct if necessary by issuing <code>date -s YYYYMMDDhhmm</code>.
# Type <code>setup-alpine</code>
# Type <code>setup-alpine</code>
# Once the installation is complete, commit the changes by typing <code>lbu commit -d</code>
# Once the installation is complete, commit the changes by typing <code>lbu commit -d</code>
Line 50: Line 76:
apk upgrade}}
apk upgrade}}


Don't forget to save the changes:
Don't forget to save the changes:{{cmd|lbu commit -d}}
 
{{cmd|lbu commit -d}}


Note: this does not upgrade the kernel. In order to upgrade the kernel, a full upgrade of the Alpine Linux version must be performed as described in [[Upgrading Alpine#Upgrading Alpine Linux on other removable media (such as CF/USB)|upgrading Alpine Linux for removable media]].
Note: this does not upgrade the kernel. In order to upgrade the kernel, a full upgrade of the Alpine Linux version must be performed as described in [[Upgrading Alpine#Upgrading Alpine Linux on other removable media (such as CF/USB)|upgrading Alpine Linux for removable media]].


=== Clock-related error messages ===
=== Linux Kernel Graphics Modes ===
 
During the booting time, you might notice errors related to the hardware clock.  The Raspberry Pi does not have
a hardware clock, thus you need to disable the hwclock daemon and enable swclock:
 
{{cmd|rc-update add swclock boot    # enable the software clock
rc-update del hwclock boot    # disable the hardware clock}}
 
Since the Raspberry Pi does not have a clock, Alpine Linux needs to know what the time is by using a
[https://en.wikipedia.org/wiki/Network_Time_Protocol Network Time Protocol (NTP)] daemon.  Make sure you have a
NTP daemon installed and running.  If you are not sure, you can install an NTP client by running the following
command:
 
{{cmd|setup-ntp}}
 
The Busybox NTP client might be the most lightweight solution.  Save the changes and reboot, once the NTP software is
installed and running:
 
{{cmd|lbu commit -d
reboot}}
 
After reboot, make sure the <code>date</code> command outputs the correct date and time.
 
=== WiFi on boot ===
If you have already [[Connecting_to_a_wireless_access_point|configured WiFi]] during the setup, the connection will not return on reboot.
You will need to start up a service to automatically connect to the wireless access point.
# Run <code>rc-update add wpa_supplicant boot</code> to connect to the wireless access point during bootup.
# Run it manually with <code>/etc/init.d/wpa_supplicant start</code>.


=== Enable OpenGL (Raspberry Pi 3/4) ===
By default system configuration will use legacy video driver: this driver has some limitations and is lacking support.<br>
Remount the boot partition writeable (i.e. <code>/media/mmcblk0p1</code>):
It is recommended to enable Linux DRM-KMS driver by adding the following to '''usercfg.txt''':
 
  # Enable DRM VC4 V3D driver
{{cmd|mount /media/mmcblk0p1 -o rw,remount}}
 
Add the following lines to <code>/media/mmcblk0p1/config.txt</code>:
 
gpu_mem=128
  # Raspberry Pi 3:
  dtoverlay=vc4-kms-v3d
  dtoverlay=vc4-kms-v3d
  # Raspberry Pi 4:
max_framebuffers=2
  dtoverlay=vc4-fkms-v3d
# Don't have the firmware create an initial video= setting in cmdline.txt.
  # Use the kernel's default instead.
  disable_fw_kms_setup=1
Note: This overlay disables legacy video [https://www.raspberrypi.com/documentation/computers/legacy_config_txt.html#legacy-video-options options].


256MB (and more on the Raspberry Pi 4) <code>gpu_mem</code> is also possible.
Install the Mesa drivers (Pi4 and Pi5):{{cmd|apk add {{pkg|mesa-dri-gallium|arch=a*}}}}


Install the Mesa drivers:
Then reboot:{{cmd|lbu_commit -d; reboot}}


{{cmd|<nowiki># Raspberry Pi 3:
=== Wireless drivers ===
apk add mesa-dri-vc4
# Raspberry Pi 4:
apk add mesa-dri-gallium</nowiki>}}


Then reboot:
As of Alpine 3.17, Wifi and Bluetooth drivers are available within install image: they are part of <code>linux-firmware-brcm</code> (and linked dependencies). Since kernel 6.1.25 (i.e. Alpine 3.18), onboard bluetooth is enabled & autoprobed by default. This may be disabled by setting [https://github.com/raspberrypi/rpi-firmware/tree/master/overlays krnbt] off).


{{cmd|lbu_commit -d; reboot}}
=== Picam ===


=== WiFi drivers ===
{{Note|The below instructions to get picam to work with Pi Zero 2 W model has been tested in [[Classic install or sys mode on Raspberry Pi|sys mode]] only.}}
As of Alpine 3.14, the WiFi drivers for the Raspberry Pi were moved from <code>linux-firmware-brcm</code> to the <code>linux-firmware-cypress</code> package (source?). Since the images seem to be an outdated version of the former, Wi-Fi will work during installation, but after the first update it will break.
Use the ethernet interface to download the required packages:


{{cmd|apk add linux-firmware-cypress}}
# Upgrade to [[Repositories#Upgrading_to_edge|edge]] version as {{pkg|rpicam-apps|arch=}} package is not yet supported in v3.21.
# Setup eudev as device manager:{{Cmd|# setup-devd udev}}
# Add <Code>camera_auto_detect=1</Code> option to the user config file {{Path|/boot/usercfg.txt}}
# Install the package {{pkg|rpicam-apps|arch=}} available in the [[Repositories#Testing|testing]] repository.
# Due to bug {{Issue|16911}}, change the permission after every reboot as follows:{{Cmd|$ doas chmod 666 /dev/dma_heap/*}}
# Test the picam by the command {{Cmd|$ libcamera-hello --list-cameras}}


And reboot.
== Custom installation instructions ==


== Persistent storage ==
* To switch a Diskless installation to a fully disk-based installation refer [[Classic_install_or_sys_mode_on_Raspberry_Pi#Convert diskless to sys mode|Convert diskless to sys mode]].
=== Loopback image with overlayfs ===
* An alternate approach [[OverlayFS#Loopback image with overlayfs|using loopback image with overlayfs]] for memory constrained Raspberry Pi models(3A+,Pi0) with only 512M of RAM running Diskless mode.
=== Netboot ===


When you install Alpine in diskless mode, the entire system is loaded into memory at boot. If you want additional storage (for example, if you need more space than offered by your RAM) we need to create loop-back storage onto the SD card mounted with overlayfs.
The Raspberry Pi 4 bootloader can be configured to [https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#raspberry-pi-4-bootloader-configuration boot from the network]. Configure the bootloader with at least


First, make the SD card writable again and change fstab to always do so:
{{cmd|<nowiki>BOOT_ORDER=0xf142
{{cmd|mount /media/mmcblk0p1 -o rw,remount
TFTP_PREFIX=1</nowiki>}}
sed -i 's/vfat\ ro,/vfat\ rw,/' /etc/fstab}}


Create the loop-back file, this example is 1 GB:
and optionally also {{cmd|<nowiki>TFTP_IP=x.x.x.x</nowiki>}} where <code>x.x.x.x</code> is the IP address of your TFTP server.


{{cmd|dd if&#61;/dev/zero of&#61;/media/mmcblk0p1/persist.img bs&#61;1024 count&#61;0 seek&#61;1048576}}
If not configuring <code>TFTP_IP</code> in the bootloader, you'll need to configure your DHCP server to advertise the TFTP server IP address. This varies depending on your DHCP server; use the following details if applicable:


Install the ext utilities:
# Vendor class: <code>PXEClient:Arch:00000:UNDI:002001</code>
# Filename: <code>/</code>


{{cmd|apk add e2fsprogs}}
The minimal set of files that your TFTP server needs to host are:


Format the loop-back file:
# <code>bcm2711-rpi-4-b.dtb</code> (from [https://raw.githubusercontent.com/raspberrypi/firmware/master/boot/bcm2711-rpi-4-b.dtb raspberrypi/firmware/master/boot/bcm2711-rpi-4-b.dtb])
# <code>cmdline.txt</code> (see below)
# <code>config.txt</code> (see below)
# <code>fixup4.dat</code> (from [https://raw.githubusercontent.com/raspberrypi/firmware/master/boot/fixup4.dat raspberrypi/firmware/master/boot/fixup4.dat], alternatively <code>fixup4cd.dat</code> for the cut down version)
# <code>initramfs-rpi4</code> (from [https://dl-cdn.alpinelinux.org/alpine/edge/releases/aarch64/netboot/initramfs-rpi4 alpine/edge/releases/aarch64/netboot/initramfs-rpi4])
# <code>start4.elf</code> (from [https://raw.githubusercontent.com/raspberrypi/firmware/master/boot/start4.elf raspberrypi/firmware/master/boot/start4.elf], alternatively <code>start4cd.elf</code> for the cut down version)
# <code>vmlinuz-rpi4</code> (from [https://dl-cdn.alpinelinux.org/alpine/edge/releases/aarch64/netboot/vmlinuz-rpi4 alpine/edge/releases/aarch64/netboot/vmlinuz-rpi4])


{{cmd|mkfs.ext4 /media/mmcblk0p1/persist.img}}
<code>config.txt</code>:
{{cmd|<nowiki>[pi4]
kernel=vmlinuz-rpi4
initramfs initramfs-rpi4
arm_64bit=1
</nowiki>}}


Mount the storage:  
<code>cmdline.txt</code>:
{{cmd|<nowiki>modules=loop,squashfs console=ttyAMA0,115200 ip=dhcp alpine_repo=http://dl-cdn.alpinelinux.org/alpine/edge/main modloop=http://dl-cdn.alpinelinux.org/alpine/edge/releases/aarch64/netboot/modloop-rpi4</nowiki>}}


{{cmd|echo "/media/mmcblk0p1/persist.img /media/persist ext4 rw,relatime,errors&#61;remount-ro 0 0" >> /etc/fstab
Instead of using the <nowiki>http://dl-cdn.alpinelinux.org/alpine/edge/releases/aarch64/netboot/</nowiki> base URL above, pinning to a specific point in time is preferred. Raspberry Pi 4 netboot files are available from https://dl-cdn.alpinelinux.org/alpine/edge/releases/aarch64/netboot-20230329/ onward.
mkdir /media/persist
mount -a}}


Make the overlay folders, we are using the /usr directory here, but you can use /home or anything else.
With the above configured the Raspberry Pi 4 should be able to boot from the network without an SD card.
{{Warning|Overlay workdir needs to be an empty directory on the same filesystem mount as the upper directory. So each overlay must use its own workdir}}


== Enable the Serial Console ==


{{cmd|mkdir /media/persist/usr
Besides having <code>enable_uart=1</code> in ''usercfg.txt'', the kernel command-line option <var>console</var> needs to be changed to <code>console=serial0,115200</code> in ''cmdline.txt''.
mkdir /media/persist/.work_usr
echo "overlay /usr overlay lowerdir&#61;/usr,upperdir&#61;/media/persist/usr,workdir&#61;/media/persist/.work_usr 0 0" >> /etc/fstab
mount -a}}


Your /etc/fstab should look something like this:
From a Linux desktop, connect to it with something like this:
{{Cmd|/dev/cdrom      /media/cdrom    iso9660 noauto,ro 0 0
/dev/usbdisk    /media/usb      vfat    noauto,ro 0 0
/dev/mmcblk0p1 /media/mmcblk0p1 vfat rw,relatime,fmask&#61;0022,dmask&#61;0022,errors&#61;remount-ro 0 0
/media/mmcblk0p1/persist.img /media/persist ext4 rw,relatime,errors&#61;remount-ro 0 0
overlay /usr overlay lowerdir&#61;/usr,upperdir&#61;/media/persist/usr,workdir&#61;/media/persist/.work_usr 0 0}}


Now commit the changes: (optionally remove the e2fsprogs, but it does contain repair tools)
{{cmd|cu -l /dev/ttyUSB0 -s 115200}}
{{cmd|lbu_commit -d}}


Remember, with this setup if you install things and you have done this overlay for /usr, you must not commit the 'apk add', otherwise, while it boots it will try and install it to memory, not to the persistent storage.
== Troubleshooting ==


If you do want to install something small at boot, you can use `apk add` and `lbu commit -d`.
<code>raspinfo</code> utility from the {{Pkg|raspberrypi-utils-raspinfo|arch=}} package can be used as a first step to diagnose issues: it will make a log report of essential Pi system configuration, and is often used as a reference to submit questions or bug reports within Raspberry Pi community (Forums, Github, etc).


If it is something a bit bigger, then you can use `apk add` but then not commit it. It will be persistent (in /user), but be sure to check everything you need is in that directory and not in folders you have not made persistent.
After booting, you may find less system memory available than you expect, as default CPU/GPU RAM split depends on Pi models and activated settings (audio, camera, video drivers, etc). To find out how your system is actually split, use <Code>vcgencmd</Code> utility from the {{pkg|raspberrypi-utils-vcgencmd|arch=}} package as follows:{{Cmd|<nowiki># vcgencmd get_mem gpu
# vcgencmd get_mem arm</nowiki>}}


=== Traditional disk-based (sys) installation ===
To modify the memory allocation refer to [[#Customize config.txt|Customize config.txt]] section.
{{Merge|Classic install or sys mode on Raspberry Pi|There's an existing page for sys-installations on RasPi.}}


It is also possible to switch to a fully disk-based installation. This is not yet formally supported, but can be done somewhat manually. This frees all the memory otherwise needed for the root filesystem, allowing more installed packages.
=== Long boot time when running headless ===


Split your SD card into two partitions: the FAT32 boot partition described above (in this example it'll be <code>mmcblk0p1</code>) , and a second partition to hold the root filesystem (here it'll be <code>mmcblk0p2</code>). Boot and configure your diskless system as above, then create a root filesystem:
If no peripherals are connected, the system might hang for an exceptionally long period of time while it attempts to accumulate entropy.


{{cmd|apk add e2fsprogs
If this is the case, simply plugging in any USB device should work around this issue, since it increases the amount of entropy available to the kernel via interrupts.
mkfs.ext4 /dev/mmcblk0p2}}


Now do a disk install via a mountpoint. The <code>setup-disk</code> script will give some errors about syslinux/extlinux, but you can ignore them.
=== apk indicating 'No space left on device' ===
The Raspberry Pi doesn't need them to boot.


{{cmd|<nowiki>mkdir /stage
While running Raspberry Pi models(3A+,Pi0) with only 512M of RAM, a fresh Alpine Linux installation in Diskless mode will only leave around 200M for tmpfs root. It's important to keep this limitation in mind or consider [[#Custom installation instructions|alternatives]] when using these boards.  
mount /dev/mmcblk0p2 /stage
setup-disk -o /media/mmcblk0p1/MYHOSTNAME.apkovl.tar.gz /stage
# (ignore errors about syslinux/extlinux)</nowiki>}}


Add a line to <code>/stage/etc/fstab</code> to mount the Pi's boot partition again:
=== Clock-related error messages ===


{{cmd|/dev/mmcblk0p1 /media/mmcblk0p1 vfat defaults 0 0}}
During the booting time, you might notice errors related to the hardware clock.  Many Raspberry Pi do not have a hardware clock, or may have one without battery, in which case the behaviour depends on whether you physically cut power or not.


Now add a <code>root=/dev/mmcblk0p2</code> parameter to the Pi's boot command line, either <code>cmdline-rpi2.txt</code> or <code>cmdline-rpi.txt</code> depending on model:
Also, <code>setup-alpine</code> will adapt the installation to the type of Raspberry Pi you use, which means for example that on a RPI5, you will see <code>hwclock></code> service, whereas on a RPI4 it will use <code>swclock</code>. In doubt, make sure to do the installation on the target hardware.


{{cmd|<nowiki>mount -o remount,rw /media/mmcblk0p1
If you still experience clock errors, add the following line to '''/etc/chrony/chrony.conf''':
sed -i '$ s/$/ root=\/dev\/mmcblk0p2/' /media/mmcblk0p1/cmdline-rpi2.txt</nowiki>}}


You might also consider <code>overlaytmpfs=yes</code> here, which will cause the underlying SD card root filesystem to be mounted read-only, with an overlayed tmpfs for modifications which will be discarded at shutdown.
<code>makestep 0.1 3</code>  


N.B. <b>the contents of /boot will be ignored when the Pi boots</b>. It will use the kernel, initramfs, and modloop images from the FAT32 boot partition. To update the kernel, initfs or modules, you will need to manually (generate and) copy these to the boot partition or you could use bind mount, in which case,
=== Wireless support with older Alpine images ===
copying the files to boot partition manually, is not needed.


{{cmd|<nowiki>echo /media/mmcblk0p1/boot /boot none defaults,bind 0 0 >> /etc/fstab</nowiki>}}
In Alpine 3.14, the WiFi drivers for the Raspberry Pi were moved from <code>linux-firmware-brcm</code> to the <code>linux-firmware-cypress</code> package (source?). Since the images seem to be an outdated version of the former, Wi-Fi will work during installation, but after the first update it will break.
Use the ethernet interface to download the required packages:


=== Persistent Installation on Raspberry Pi 3 ===
{{cmd|apk add {{pkg|linux-firmware-cypress|arch=a*}}}}
See [[Classic install or sys mode on Raspberry Pi]] and https://web.archive.org/web/20171125115835/https://forum.alpinelinux.org/comment/1084#comment-1084


=== Persistent Installation on Raspberry Pi 4 ===
And reboot.
As of 3.14, setup-alpine should ask you if you want to create a sys mode partition on your Raspberry Pi 4.
 
== Troubleshooting ==
 
=== Long boot time when running headless ===
 
If no peripherals are connected, the system might hang for an exceptionally long period of time while it attempts to accumulate entropy.
 
If this is the case, simply plugging in any USB device should work around this issue.
 
'''Alternatively''', installing haveged, the random numbers generator, would speed up the process:
 
  apk update
  apk add haveged
  rc-update add haveged boot
  lbu commit -d
  service haveged start
 
(Tested on a raspberry pi zero W in headless mode, no USB connected, Alpine 3.10.3)
 
=== apk indicating 'No space left on device' ===
 
Note some models of the Raspberry Pi such as the 3A+ only have 512M of RAM, which on fresh Alpine deployment will only leave around 200M for tmpfs root. It's important to keep this limitation in mind when using these boards.
 
=== Wireless support with older Alpine images ===


If you need Wi-Fi, you'll need to [https://github.com/RPi-Distro/firmware-nonfree/tree/master/brcm download] the latest Broadcom drivers to your SD card.
If you need Wi-Fi, you'll need to [https://github.com/RPi-Distro/firmware-nonfree/tree/master/brcm download] the latest Broadcom drivers to your SD card.
Line 241: Line 207:
   cp firmware-nonfree/brcm/* /mnt/sdcard/firmware/brcm
   cp firmware-nonfree/brcm/* /mnt/sdcard/firmware/brcm


== See Also ==
=== Fileystem for boot partition ===
 
If you are trapped at the dreaded rainbow screen, with the green led blinking a few times in a row, repeatedly, check the boot partition type.
 
The rpi2 require '''fat32''' for the boot partition, NOT '''fat16'''.  Use linux fdisk to set the boot partition type as "c" (for fat32/lba) and set the '''lba''' and '''boot''' flags for the partition as suggested.  Create the boot partition filesystem as fat32 with:{{Cmd|mkdosfs -F 32 /dev/sdX1}}
 
== See also ==


* [[Classic install or sys mode on Raspberry Pi]] - a variant.
* [[Classic install or sys mode on Raspberry Pi]]  
* [[Raspberry Pi - Headless Installation]]
* [[Raspberry Pi 3 - Setting Up Bluetooth]]
* [[Raspberry Pi 3 - Setting Up Bluetooth]]
* [[Raspberry Pi 3 - Configuring it as wireless access point -AP Mode]]
* [[Raspberry Pi 3 - Configuring it as wireless access point -AP Mode]]
Line 250: Line 221:
* [[Linux Router with VPN on a Raspberry Pi]]
* [[Linux Router with VPN on a Raspberry Pi]]
* [[Create a bootable SDHC from a Mac]]
* [[Create a bootable SDHC from a Mac]]
* [[OverlayFS‎‎]]
* Build custom Raspberry Pi images based on Alpine via [https://github.com/tolstoyevsky/pieman Pieman]
* Build custom Raspberry Pi images based on Alpine via [https://github.com/tolstoyevsky/pieman Pieman]
* [[Tutorials and Howtos#Raspberry Pi]]
* [[Tutorials and Howtos#Raspberry Pi]]

Revision as of 08:52, 3 April 2025

This page explains how to install and use Alpine Linux on Raspberry Pi.

For scenarios where there is not expected to be significant changes to disk after setup (like running a static HTTP server), diskless mode is preferable, as running the entire system from memory will improve performance (by avoiding the slow SD card) and improve the SD card life (by reducing the writes to the card, as all logging will happen in RAM). Use Alpine Local Backup (lbu) utility to install packages, save local files, and tune the system.

sys-mode installation is more appropriate for the following use cases:

  • There will be constant changes to the disk after initial setup (for example, if you expect people to login and save files to their home directories)
  • Logs should persists across reboots
  • Plan to install packages which consume more space than can be loaded into RAM
  • Plan to install kernel modules (such as ZFS)

sys-mode with Immutable root option can also be a solution to keep whole system on read-only media (lower RAM requirement than diskless mode which loads whole system in RAM) while avoiding SD wear as runtime files are mapped to tmpfs in RAM (check limitations).

Compatibility list

Refer to the information regarding Raspberry Pi models in the below table when choosing image/file to download from Downloads page for your device. Verify the downloaded image before proceeding further.

Alpine Linux Hardware Support Matrix
Architecture Port Description Since
x86 x86 32 bit i686 compatible (or later) CPUs with at least CMOV and SSE2 All
x86_64 AMD64 compatible 64-bit x86 instruction set All
ARM armhf 32 bit ARM with hard-float ABI - for ARMv6 devices- Raspberry Pi 1, Zero, ZeroW, cm1 (defconfig bcmrpi) v3.0
armv7 32 bit ARM - for ARMv7 devices - Raspberry Pi 2, 3, 3+, Zero2W, cm3, cm3+ (defconfig bcm2709) v3.9
aarch64 64 bit ARM - for ARMv8+ devices - Raspberry Pi 3, 3+, 4, 400, Zero2W, cm3, cm3+, cm4, 5 (defconfig bcm2711) v3.5
PowerPC ppc64le 64 bit PowerPC (little-endian) mostly for POWER8 and POWER9 v3.6
IBM System Z s390x IBM Z mainframes, especially IBM Z and IBM LinuxONE (z196 minimum) v3.6
RISC V riscv64 64 bit RISC V v3.20
LoongArch loongarch64 64 bit LoongArch v3.21

Preparing for the installation

Irrespective of the Install media size, the fat partition size created when using the disk image is around 100Mb. If you need a bigger partition (highly recommended for diskless), proceed to download the tarball and follow the Manual method.

Raspberry Pi Imager

Raspberry Pi Imager is an utility for writing a disk image file to a micro-SD card to be used as install media. When using the above utility, there is neither a need to download the image nor partition and format the media. This utility is available on Linux/macOS/Windows.

In Alpine linux, Install the rpi-imager package for the Raspberry Pi Imager utility. Follow the prompts and install media will be generated with few clicks. To launch the utility in graphical mode issue the command:

rpi-imager

--cli option is also available. For complete usage guide, check out the rpi-imager(1) manpages, which you can install with the rpi-imager-doc package.

Proceed to Installation, if no further customization is required.

Manual method

Alternatively, image or tarball may be downloaded, and SD card media formatted and prepared as per below:

  • Download the Alpine Linux image or tarball for Raspberry Pi . Use the compability list above when choosing image/tarball to download.
  • Create a bootable FAT32 partition on your SD card. The partitioning and formatting part of the instructions on the linked page could be done using a graphical partitioning tool such as gnome-disks, just make sure the partition type is W95 FAT32 (LBA). (The current type can be found in the "Type" column in the output of fdisk -l.)
    Tip: to reduce SD wear risk, it is advised to keep at least 10% of capacity as unallocated space. If media was previously partitioned at full capacity, running blkdiscard /dev/mmcblk0 makes sure to discard device sectors before re-partitioning.
    Warning: Do not use the volume label boot for the fat32 partition. Due to an upstream bug, kernel/initramfs cannot be loaded from subdirectory with same name as volume label. Since kernel is installed to boot/ folder in Alpine Linux, do not use the volume label boot for the fat32 partition.

  • Extract the tarball to the root of the bootable FAT32 partition.

Customize config.txt

Instead of the BIOS found on a conventional PC, Raspberry Pi devices use a configuration file called config.txt. The GPU reads config.txt before the Arm CPU and Linux initialise. It is recommended to create a usercfg.txt file on boot partition to configure low-level system settings, as config.txt may be replaced during bootloader/system upgrades. Settings details can be found here. However, some settings can only be set in config.txt, and will have no effect when specified in usercfg.txt (e.g. gpu_mem).

Some interesting values include:

Contents of usercfg.txt

enable_uart=1 # To enable the UART console: dtparam=audio=on # To enable audio
  • By default system will use legacy video driver: some options may be used to adjust displays modes (e.g. if you see black edges around your screen after booting the Pi, you can add disable_overscan=1). Alternatively Linux DRM-KMS driver may be used (see below).
  • If you plan to install on a Pi Computer Module 4 with I/O board, you may need to add: otg_mode=1
  • Pi Zeros/A/A+/3A+/4B/400/5/500/CMs may be configured as USB serial-gadget (i.e. console access for setup) or ethernet-gadget networking: add dtoverlay=dwc2,dr_mode=peripheral in usercfg.txt and modules=g_cdc in cmdline.txt
  • To maximize available CPU memory if not requiring extra GPU features (i.e. headless/CLI use-cases), cut-down bootloader may be installed with raspberrypi-bootloader-cutdown package, and activated by adding gpu_mem=16 in config.txt (setting may be wiped after bootloader package update).

Installation

See also: Classic install or sys mode on Raspberry Pi
Tip: To install Alpine Linux on a pi without keyboard, mouse & display, additional preparatory steps are available at headless Installation page.

Follow these steps to install Alpine Linux in Diskless Mode:

  1. Insert the SD card into the Raspberry Pi and power it on
  2. Login into the Alpine system as root. Leave the password empty.
  3. Check the current date and time by issuing date. Correct if necessary by issuing date -s YYYYMMDDhhmm.
  4. Type setup-alpine
  5. Once the installation is complete, commit the changes by typing lbu commit -d

Type reboot to verify that the installation was indeed successful.

Post Installation

Update the System

After installation, make sure your system is up-to-date:

apk update apk upgrade

Don't forget to save the changes:

lbu commit -d

Note: this does not upgrade the kernel. In order to upgrade the kernel, a full upgrade of the Alpine Linux version must be performed as described in upgrading Alpine Linux for removable media.

Linux Kernel Graphics Modes

By default system configuration will use legacy video driver: this driver has some limitations and is lacking support.
It is recommended to enable Linux DRM-KMS driver by adding the following to usercfg.txt: 

# Enable DRM VC4 V3D driver
dtoverlay=vc4-kms-v3d
max_framebuffers=2

# Don't have the firmware create an initial video= setting in cmdline.txt.
# Use the kernel's default instead.
disable_fw_kms_setup=1

Note: This overlay disables legacy video options.

Install the Mesa drivers (Pi4 and Pi5):

apk add mesa-dri-gallium

Then reboot:

lbu_commit -d; reboot

Wireless drivers

As of Alpine 3.17, Wifi and Bluetooth drivers are available within install image: they are part of linux-firmware-brcm (and linked dependencies). Since kernel 6.1.25 (i.e. Alpine 3.18), onboard bluetooth is enabled & autoprobed by default. This may be disabled by setting krnbt off).

Picam

Note: The below instructions to get picam to work with Pi Zero 2 W model has been tested in sys mode only.
  1. Upgrade to edge version as rpicam-apps package is not yet supported in v3.21.
  2. Setup eudev as device manager:

    # setup-devd udev

  3. Add camera_auto_detect=1 option to the user config file /boot/usercfg.txt
  4. Install the package rpicam-apps available in the testing repository.
  5. Due to bug #16911, change the permission after every reboot as follows:

    $ doas chmod 666 /dev/dma_heap/*

  6. Test the picam by the command

    $ libcamera-hello --list-cameras

Custom installation instructions

Netboot

The Raspberry Pi 4 bootloader can be configured to boot from the network. Configure the bootloader with at least

BOOT_ORDER=0xf142 TFTP_PREFIX=1

and optionally also

TFTP_IP=x.x.x.x

where x.x.x.x is the IP address of your TFTP server.

If not configuring TFTP_IP in the bootloader, you'll need to configure your DHCP server to advertise the TFTP server IP address. This varies depending on your DHCP server; use the following details if applicable:

  1. Vendor class: PXEClient:Arch:00000:UNDI:002001
  2. Filename: /

The minimal set of files that your TFTP server needs to host are:

  1. bcm2711-rpi-4-b.dtb (from raspberrypi/firmware/master/boot/bcm2711-rpi-4-b.dtb)
  2. cmdline.txt (see below)
  3. config.txt (see below)
  4. fixup4.dat (from raspberrypi/firmware/master/boot/fixup4.dat, alternatively fixup4cd.dat for the cut down version)
  5. initramfs-rpi4 (from alpine/edge/releases/aarch64/netboot/initramfs-rpi4)
  6. start4.elf (from raspberrypi/firmware/master/boot/start4.elf, alternatively start4cd.elf for the cut down version)
  7. vmlinuz-rpi4 (from alpine/edge/releases/aarch64/netboot/vmlinuz-rpi4)

config.txt:

[pi4] kernel=vmlinuz-rpi4 initramfs initramfs-rpi4 arm_64bit=1

cmdline.txt:

modules=loop,squashfs console=ttyAMA0,115200 ip=dhcp alpine_repo=http://dl-cdn.alpinelinux.org/alpine/edge/main modloop=http://dl-cdn.alpinelinux.org/alpine/edge/releases/aarch64/netboot/modloop-rpi4

Instead of using the http://dl-cdn.alpinelinux.org/alpine/edge/releases/aarch64/netboot/ base URL above, pinning to a specific point in time is preferred. Raspberry Pi 4 netboot files are available from https://dl-cdn.alpinelinux.org/alpine/edge/releases/aarch64/netboot-20230329/ onward.

With the above configured the Raspberry Pi 4 should be able to boot from the network without an SD card.

Enable the Serial Console

Besides having enable_uart=1 in usercfg.txt, the kernel command-line option console needs to be changed to console=serial0,115200 in cmdline.txt.

From a Linux desktop, connect to it with something like this:

cu -l /dev/ttyUSB0 -s 115200

Troubleshooting

raspinfo utility from the raspberrypi-utils-raspinfo package can be used as a first step to diagnose issues: it will make a log report of essential Pi system configuration, and is often used as a reference to submit questions or bug reports within Raspberry Pi community (Forums, Github, etc).

After booting, you may find less system memory available than you expect, as default CPU/GPU RAM split depends on Pi models and activated settings (audio, camera, video drivers, etc). To find out how your system is actually split, use vcgencmd utility from the raspberrypi-utils-vcgencmd package as follows:

# vcgencmd get_mem gpu # vcgencmd get_mem arm

To modify the memory allocation refer to Customize config.txt section.

Long boot time when running headless

If no peripherals are connected, the system might hang for an exceptionally long period of time while it attempts to accumulate entropy.

If this is the case, simply plugging in any USB device should work around this issue, since it increases the amount of entropy available to the kernel via interrupts.

apk indicating 'No space left on device'

While running Raspberry Pi models(3A+,Pi0) with only 512M of RAM, a fresh Alpine Linux installation in Diskless mode will only leave around 200M for tmpfs root. It's important to keep this limitation in mind or consider alternatives when using these boards.

Clock-related error messages

During the booting time, you might notice errors related to the hardware clock. Many Raspberry Pi do not have a hardware clock, or may have one without battery, in which case the behaviour depends on whether you physically cut power or not.

Also, setup-alpine will adapt the installation to the type of Raspberry Pi you use, which means for example that on a RPI5, you will see hwclock> service, whereas on a RPI4 it will use swclock. In doubt, make sure to do the installation on the target hardware.

If you still experience clock errors, add the following line to /etc/chrony/chrony.conf:

makestep 0.1 3

Wireless support with older Alpine images

In Alpine 3.14, the WiFi drivers for the Raspberry Pi were moved from linux-firmware-brcm to the linux-firmware-cypress package (source?). Since the images seem to be an outdated version of the former, Wi-Fi will work during installation, but after the first update it will break. Use the ethernet interface to download the required packages:

apk add linux-firmware-cypress

And reboot.

If you need Wi-Fi, you'll need to download the latest Broadcom drivers to your SD card. (Replace /mnt/sdcard with the correct mount point.) 

 git clone --depth 1 https://github.com/RPi-Distro/firmware-nonfree.git
 cp firmware-nonfree/brcm/* /mnt/sdcard/firmware/brcm

Fileystem for boot partition

If you are trapped at the dreaded rainbow screen, with the green led blinking a few times in a row, repeatedly, check the boot partition type.

The rpi2 require fat32 for the boot partition, NOT fat16. Use linux fdisk to set the boot partition type as "c" (for fat32/lba) and set the lba and boot flags for the partition as suggested. Create the boot partition filesystem as fat32 with:

mkdosfs -F 32 /dev/sdX1

See also

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