Alpine on the Olimex A20 OLinuXino Lime2 - Short Version

by Edin Tarić - updated

Update 2023-01

Since this whole process is long, arduous and repetitive, I have written a script that allows you to do this fully automatically, either with pre-supplied options or interactively: Codeberg.org - alpine-a20-olinuxino-lime2

Preparation

Wipe the start of your uSD card:

$ doas dd if=/dev/zero of=$sdcard bs=1 count=1M

Create empty MBR/dos disklabel:

$ echo "label: dos" | doas sfdisk $sdcard

Single partition

To create a single bootable Ext4 partition, we use the following command:

$ echo "type=83, bootable" | doas sfdisk --wipe-partitions always $sdcard

“type=83” means that the partition type is “Linux”, which is used for ext4

Multiple partitions

Example creating partition 1 that is 4GB in size, partition 2 that takes the rest of the space:

$ printf "size=4GiB, type=83, bootable\ntype=83" | doas sfdisk --wipe-partitions always $sdcard

For each partition you want to create, you pass one line of input to sfdisk, so you can create more by adding more lines

For more details about all possible options, please refer to the sfdisk(8) manpage.

Creating the filesystems

$ doas mkfs.ext4 $partition

U-Boot

Installing dependencies:

For Alpine:

$ doas apk add alpine-sdk bc bison dtc flex gcc-arm-none-eabi linux-headers \
ncurses-dev openssl-dev perl python3 py3-setuptools python3-dev sdl2-dev swig

Instructions for other OS: u-boot.readthedocs.io - Build U-Boot

Getting U-Boot:

$ git clone https://source.denx.de/u-boot/u-boot.git
$ cd u-boot
$ git checkout v2022.10

Configuring U-Boot:

For the eMMC version of the board, edit configs/A20-OLinuXino-Lime2-eMMC_defconfig For non-eMMC version of the board, edit configs/A20-OLinuXino-Lime2_defconfig

For board revisions A-E:

For board revisions F-G2:

For board revisions H and later:

Compiling U-Boot

After we are done editing the defconfig file, we have to run one of these two commands depending on whether or not you have eMMC:

$ make A20-OLinuXino-Lime2_defconfig      # without eMMC
$ make A20-OLinuXino-Lime2-eMMC_defconfig # with eMMC

Finally, we run ‘make’ to build u-boot:

CROSS_COMPILE=arm-none-eabi- make

Flashing U-Boot

$ doas dd if=u-boot-sunxi-with-spl.bin of=$sdcard bs=1024 seek=8

Alpine Linux

Download alpine and its hash, then verify it:

$ wget https://dl-cdn.alpinelinux.org/alpine/v3.17/releases/armv7/alpine-uboot-3.17.0-armv7.tar.gz
$ wget https://dl-cdn.alpinelinux.org/alpine/v3.17/releases/armv7/alpine-uboot-3.17.0-armv7.tar.gz.sha256
$ sha256sum -c alpine-uboot-3.17.0-armv7.tar.gz.sha256

Mount the bootable partition we created:

$ mkdir mnt
$ doas mount $partition mnt/

Extract alpine archive onto the partition:

$ doas tar -xzf alpine-uboot-3.17.0-armv7.tar.gz -C mnt/

Copy device tree binary to the partition:

$ doas cp u-boot/u-boot.dtb mnt/boot/

Edit the file “mnt/extlinux/extlinux.conf” to make sure it uses our “u-boot.dtb” file instead of the default:

TIMEOUT 10
PROMPT 1
DEFAULT lts

LABEL lts
MENU LABEL Linux lts
KERNEL /boot/vmlinuz-lts
INITRD /boot/initramfs-lts
FDT /boot/u-boot.dtb
APPEND modules=loop,squashfs,sd-mod,usb-storage quiet

Sync and unmount the partition:

$ doas sync
$ doas umount mnt/

Now you can boot and install alpine. You can see the board’s output either via serial or the HDMI port. From there onwards you can follow the official installation documentation: wiki.alpinelinux.org - Installation

Conclusion

If you have any trouble or any other questions or suggestions, feel free to send me an email to contact@regrow.earth!