Alpine on ARM: Difference between revisions

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Preparing installation media

There are no installation images for ARM, since different boards require slightly different builds of u-boot. Hence, preparation steps are a bit more involved than x86_64.

The latest images are available on the Alpine Linux downloads page.

In case the download page provides no specific image for your particular board, download the "Generic ARM" image. armv7 is the most compatible and aarch64 is the best choice for modern ARM SoCs.

Formating the sd card

To install Alpine, an SD card is required, and it will be completely wiped while preparing it for use as installation media.

Insert the SD card onto the host where you've downloaded the Alpine tarball and find out its devices name with dmesg or fdisk -l.

Tip: Useful hints about basic identification of and access to your SD card or USB target device, may also be found in the general instructions at https://wiki.alpinelinux.org/wiki/Installation.

Create a partition in the SD card. The usual choice is to use doas fdisk /dev/sdX. Care must be taken when creating the partition; it should never overlap with the u-boot (which will be set up in the following step). It is recommended to use start: 32768 as a safe choice when creating the partition. Make sure that the partition is also marked as bootable.

It is also recommended to use FAT32, since ext4 is sometimes problematic with GRUB2, so set the partition type to W95 FAT32 (LBA).

Once the partition has been created, it needs to be formatted. Use, for example: mkfs.vfat /dev/sdX1

Copying installation files onto the sd card

Now extract the downloaded tarball into the SD card:

doas mount /dev/sdX1 /mnt
cd /mnt
doas tar -xf $HOME/downloads/alpine-uboot-3.18.2-aarch64.tar.gz

Installing u-boot onto the SD card

Finally, u-boot needs to be installed into the SD card. The exact steps vary per board. The following example installs u-boot for a pinebook-pro:

# Copy the U-Boot TPL/SPL
doas dd if=u-boot/pinebook-pro-rk3399/idbloader.img of=/dev/sdb bs=512 seek=64 conv=notrunc
# Copy u-boot.itb itself
doas dd if=u-boot/pinebook-pro-rk3399/u-boot.itb of=/dev/sdb bs=512 seek=16384 conv=notrunc

For rk3399-based boards, these steps should be quite similar. Other boards are an exercise left to the reader.

Installing Alpine

Insert the SD card into the ARM board, and turn it on. At this point, you should continue the general installation process as described in the Installation#Installation_Step_Details.

Note: Installing packages with `apk` fails with a certificate warning if the system time is too far off, i.e. by default on boards without an internal real time clock (RTC). So make sure to first adjust the clock properly.

Supported SoCs

Alpine is compiled with support files for so many formidable SoCs — besides the Raspberry Pi — that to find out about a particular chipset's support it can be useful to refine the search for all *.dtb files in the package database (i.e. filter for "*<some-board-or-SoC-identifying-string>*.dtb" file).

For example, by refining the following search in the current "edge" release:

DTB-files in the current edge branch: https://pkgs.alpinelinux.org/contents?repo=main&file=*.dtb&branch=edge

Fully supported boards are those for which there is a working bootloader shipped in the download.

Installing Alpine on Supported Boards

Installation on a Wandboard

Follow the steps above on Preparing installation media. To install u-boot into the SD card, use:

dd if=u-boot/wandboard/SPL of=/dev/sdX seek=1 bs=1k
dd if=u-boot/wandboard/u-boot.img of=/dev/sdX seek=69 bs=1k

Finally, put the SD card in the Wandboard and boot it with a serial console connected.

The board should now boot from the SD card. When the prompt asks for a login, you can follow the Alpine Linux Installation instructions to run setup-alpine as usual.

More specific guides

Installing Alpine on boards without full support

If you have, for example, an armv6/armv7 board that is not fully supported, but whose SoC is already supported by the mainline kernel and uboot, then it's still possible to install Alpine. It may involve a couple more manual steps.

Requirements

Alpine's forked uboot to support tarballs (fabled?)
serial console
crosscompiler/toolchain if you can not compile natively

The embedded world

A lot of the SoCs have their own way of doing things, although they use uboot and Linux kernel but often they are heavily modified to suit easy flashing of "ROMs" or other unknown reasons, e.g. Rockchip's notion "partition" are neither DOS nor GPT partitions. Here, we will try to install Alpine in a more standard way, like on the x86 platform, with either DOS or GPT partitions. To boot this, you will most likely have to install/flash the mainline uboot, which can be non-destructive if you can load it from external storage.

Storage

One can load uboot from the following block devices if it's supported.

NAND
eMMC
SD card
USB

Power on

Some SoCs need both SPL and uboot, you need to check uboot for your board. Most (if not all) boards boots from the internal storage first (either NAND or eMMC) you will have to check documentation of your board if you wish to boot the SPL/uboot from SD/USB.

One can view SPL+uboot as BIOS and boot-loader on PC. Think that you could put the BIOS on an external storage :D

Once you have loaded the "standard" uboot, things are more or less like on x86.

Booting Linux kernel

uboot uses extlinux.conf file to locate the kernel/initramfs/... just like syslinx, you need to put that file on the partitions which is marked bootable in the /boot directory
there should be an extra line "FDTDIR" which points to the DTBs

e.g.

label Fedora (3.17.0-0.rc4.git2.1.fc22.armv7hl) 22 (Rawhide)
	kernel /boot/vmlinuz-3.17.0-0.rc4.git2.1.fc22.armv7hl
	append ro root=UUID=8eac677f-8ea8-4270-8479-d5ddbb797450 console=ttyS0,115200n8 LANG=en_US.UTF-8 drm.debug=0xf
	fdtdir /boot/dtb-3.17.0-0.rc4.git2.1.fc22.armv7hl
	initrd /boot/initramfs-3.17.0-0.rc4.git2.1.fc22.armv7hl.img

Using QEMU

qemu-system-arm -M vexpress-a9 -kernel zImage -initrd initramfs-grsec -dtb vexpress-v2p-ca9.dtb -hda hda.img -serial stdio

@@ Line 3: / Line 3: @@
 {{Move|ARM SoCs}}
-(Parts of this page are still incomplete and might even need corrections.)
+== Preparing installation media ==
+There are no installation images for ARM, since different boards require slightly different builds of u-boot. Hence, preparation steps are a bit more involved than x86_64.
-==Supported SoCs==
+The latest images are available [https://alpinelinux.org/downloads/ on the Alpine Linux downloads page].
-{{Note|Installing packages with `apk` fails with a certificate warning if the system time is too far off, i.e. by default on boards without an internal real time clock (RTC). So make sure to first adjust the clock properly.}}
-Alpine is compiled with support files for so many formidable SoCs — besides the Raspberry Pi — that to find out about a particular chipset's support it can be useful to refine the search for all <code>*.dtb</code> files in the package database (i.e. filter for "<code>*<some-board-or-SoC-identifying-string>*.dtb</code>" file).
+In case the download page provides no specific image for your particular board, download the "Generic ARM" image. armv7 is the most compatible and aarch64 is the best choice for modern ARM SoCs.
-For example, by refining the following search in the current "edge" release:
+=== Formating the sd card ===
-DTB-files in the current edge branch:
+To install Alpine, an SD card is required, and it will be completely wiped while preparing it for use as installation media.
-https://pkgs.alpinelinux.org/contents?repo=main&file=*.dtb&branch=edge
-Fully supported boards are those for which there is a working bootloader shipped in the download.
+Insert the SD card onto the host where you've downloaded the Alpine tarball and find out its devices name with <code>dmesg</code> or <code>fdisk -l</code>.
-==Installing Alpine on Supported Boards==
+{{Tip|Useful hints about basic identification of and access to your SD card or USB target device, may also be found in the general instructions at https://wiki.alpinelinux.org/wiki/Installation.}}
-=== Get latest Alpine image ===
+Create a partition in the SD card. The usual choice is to use <code>doas fdisk /dev/sdX</code>. Care must be taken when creating the partition; it should never overlap with the u-boot (which will be set up in the following step). It is recommended to use <code>start: 32768</code> as a safe choice when creating the partition. Make sure that the partition is also marked as bootable.
-The latest images are available [https://alpinelinux.org/downloads/ on the Alpine Linux downloads page].
+It is also recommended to use FAT32, since ext4 is sometimes problematic with GRUB2, so set the partition type to <code>W95 FAT32 (LBA)</code>.
-In case the download page provides no specific image for your particular board, download the "Generic ARM" image.
+Once the partition has been created, it needs to be formatted. Use, for example: <code>mkfs.vfat /dev/sdX1</code>
-The <code>*.tar.gz</code> files (aka "tarballs") need to be extracted to some boot media device.
+=== Copying installation files onto the sd card ===
-{{Tip|Useful hints about basic identification of and access to your SD card or USB target device, may also be found in the general instructions at https://wiki.alpinelinux.org/wiki/Installation.}}
+Now extract the downloaded tarball into the SD card:
-After extracting the files onto a USB drive or SD card, some devices, typically those using widely used standards, possibly basic boot selection jumpers, or featuring an internal flash chip with a modern bootloader, possibly with boot menu, may allow to boot the media right away.
+ doas mount /dev/sdX1 /mnt
+ cd /mnt
+ doas tar -xf $HOME/downloads/alpine-uboot-3.18.2-aarch64.tar.gz
-However, if your device (even with its internal bootloader firmware, if any, updated to the latest version) is not able to boot the media as is, then some specific adjustment of the boot media (according to the requirements of your device) is needed to allow booting.
+=== Installing u-boot onto the SD card ===
+Finally, u-boot needs to be installed into the SD card. The exact steps vary per board. The following example installs u-boot for a pinebook-pro:
-=== Preparation of adjusted boot media in general ===
+ # Copy the U-Boot TPL/SPL
+ doas dd if=u-boot/pinebook-pro-rk3399/idbloader.img of=/dev/sdb bs=512 seek=64 conv=notrunc
+ # Copy u-boot.itb itself
+ doas dd if=u-boot/pinebook-pro-rk3399/u-boot.itb of=/dev/sdb bs=512 seek=16384 conv=notrunc
-Here we are using an SD card and the "Wandboard" as a rather generic example. If your particular board happens to require something to boot Alpine that is not mentioned here, or in any more specific documents link below, please consider adding the missing info, e.g. by adding to the links below.
+For rk3399-based boards, these steps should be quite similar. Other boards are an exercise left to the reader.
-Start by extracting the archive somewhere.
+=== Installing Alpine ===
-If needed, manually (re-)partition the boot media.
+Insert the SD card into the ARM board, and turn it on. At this point, you should continue the general installation process as described in the [[Installation#Installation_Step_Details]].
-Either DOS or GPT patitions should work. However, the start of the first partition should be on block 2048 so there is enough space before it for the SPL and uboot code. And the partition should be marked bootable (with the MBR bootable flag, or GPT legacy_bios_bootable attribute).
+{{Note|Installing packages with `apk` fails with a certificate warning if the system time is too far off, i.e. by default on boards without an internal real time clock (RTC). So make sure to first adjust the clock properly.}}
-Then install the SoCs particular boot loader(s) to the places on the SD card where the device expects them, e.g. the SPL and u-boot.img (this differs between boards).
+== Supported SoCs ==
-* SPL often starts at block 64 (but please consult the docs for your board)
+Alpine is compiled with support files for so many formidable SoCs — besides the Raspberry Pi — that to find out about a particular chipset's support it can be useful to refine the search for all <code>*.dtb</code> files in the package database (i.e. filter for "<code>*<some-board-or-SoC-identifying-string>*.dtb</code>" file).
-* uboot often starts at block 256 (please consult the docs for your board)
-Just write the SPL and uboot with the correct offset to the media you wish to boot:
+For example, by refining the following search in the current "edge" release:
-As user root, and from the location of the extracted image files, do a direct disk (dd) write using as input file the SPL from the extracted Alpine image, and the SD card (here <code>/dev/sdX</code>) as output file node (the target device).
+DTB-files in the current edge branch:
+https://pkgs.alpinelinux.org/contents?repo=main&file=*.dtb&branch=edge
-For the SPL on the Wandboard, that is:
+Fully supported boards are those for which there is a working bootloader shipped in the download.
-{{Cmd|dd if{{=}}u-boot/wandboard/SPL of{{=}}/dev/sdX seek{{=}}1 bs{{=}}1k}}
+==Installing Alpine on Supported Boards==
-Similarly, for the u-boot.img on the wandboard:
+=== Installation on a Wandboard ===
-{{Cmd|dd if{{=}}u-boot/wandboard/u-boot.img of{{=}}/dev/sdX seek{{=}}69 bs{{=}}1k}}
+Follow the steps above on [[Alpine_on_ARM#Preparing installation media|Preparing installation media]].  To install u-boot into the SD card, use:
-Now, format the partition on the SD card, mount it, and copy the folders <code>apks/</code>, <code>boot/</code>, <code>efi/</code>, <code>extlinux/</code>, and <code>u-boot/</code> to the SD card partition. (I'm not sure if all folders are needed).
+ dd if=u-boot/wandboard/SPL of=/dev/sdX seek=1 bs=1k
+ dd if=u-boot/wandboard/u-boot.img of=/dev/sdX seek=69 bs=1k
 Finally, put the SD card in the Wandboard and boot it with a serial console connected.
 The board should now boot from the SD card. When the prompt asks for a login, you can follow [[Installation|the Alpine Linux Installation instructions]] to run <code>setup-alpine</code> as usual.
 === More specific guides ===