Olinuxino Lime2 (A20 - arm) and Trisquel: Has anyone done it?

Hi nparafe,

I have successfully setup trisquel on arm (A20) devices, namely the cubieboard 2 and banana pi. I am working on a guide do these at the moment. It should work for the Olinuxino Lime2 to as these are supported by the u-boot images in trisquel.

I'd say its not much different to how to setup parabola on the same devices, but there are some extra steps, currently there is a need to use the fsfla prebuilt kernel images and chrooting in order to setup the system. A (very simplified) order goes something like, format the SD card to ext4, mount it and unpack the trisquel arm rootfs image, then chroot- install u-boot and flash, update, setup the system (adding users and ntp etc) setup the fsfla flash repo and install the kernel and config u-boot/extlinux/dtb. After which it should all boot.

Its sounds more complicated than it really is, There isn't too many commands needed in order to get setup, but there is a sequence. Once you get into it it probably only takes maybe 15-30 mins.

I will make a consented effort to finish documenting my findings, but I sometimes procrastinate but I have half completed it. Sorry.

Hope this helps in some way for now,

Ryan

> I will make a consented effort to finish documenting my findings
That sounds awesome.

In the meantime, I would appreciate if someone can explain the steps in more detail, especially:
> chroot- install u-boot and flash, update,
> ...install the kernel and config u-boot/extlinux/dtb

> For what I can understand, Trisquel on arm devices is somewhat tricky.

Actually, as an owner of many exotic devices, installing any OS on ARM/RISCV SBCs is somewhat tricky.

> I would appreciate if someone can explain the steps in more detail, especially:

>> chroot- install u-boot and flash, update,
>> ...install the kernel and config u-boot/extlinux/dtb

That's actually many steps meld into two. I usually do it in the order like this: prepare a rootfs using debootstrap; install linux-image-arm64; install u-boot.

U-boot can read/write ext4 filesystems, unlike EFI, so you can just make one ext4 partition.

Basically you need to have another working Trisquel or debian-derivative system, mount your storage device (formatted), then run the debootstrap command (install deboostrap first). e.g. (assuming mounted at /mnt):

debootstrap aramo /mnt http://repo.jing.rocks/trisquel

* the URL should be a Trisquel mirror. This URL is the mirror I host. :) If you don't provide an URL it will default to debian's apt repo.

debootstrap will download and extract packages, thus building a minimal rootfs. When it finishes, it's time to chroot, but we also need some more mounting to work inside the chroot:

mount --bind /dev /mnt/dev
mount -t proc proc /mnt/proc
mount -t sysfs sysfs /mnt/sys
mount -t tmpfs tmpfs /mnt/tmp # optional
chroot /mnt

Note that if you are bootstraping a foreign architecture, e.g., your amd64 laptop to your arm64 SBC, you likely need the qemu-user-static package, so that you can run arm64 binaries (via qemu) on your amd64 laptop.

Once you are inside the chroot, there are a few things to do:
1. set root passwd.
2. set localtime.
3. set hostname.
4. adjust "/etc/apt/sources.list", like adding aramo-updates and aramo-security
5. set locales to generate in "/etc/locale.gen". You likely need to install the locales package first.
6. setup /etc/fstab
7. (maybe) setup networking. or not.
8. do you need other software? I always need bash-completion.

Then we can install a kernel. "linux-image-arm64" should just work.

If Trisquel doesn't come with a u-boot-* package for your board, you will need to compile u-boot yourself. This is board specific and you should consult u-boot manual for instructions. The u-boot binary will need to be "flashed" to somewhere (SD card, emmc, SPI falsh?), and it's also board specific, consult u-boot manual or your board manual.

U-boot's "standard boot" supports multiple ways of telling it where to find your kernel image, it searches e.g. /boot/extlinux/extlinux.conf, /boot/boot.scr, and this part is kind of hard to explain...FIXME

You might also want to add a hook for initramfs to copy dtb from /usr/lib/linux-image-$KERNELVERSION-arm64 to /boot/dtb/, then use the u-boot-tool to mkimage to convert initrd.img to uInitrd (a gzipped format that u-boot recognizes). Again the setup is kind of complex. From what I observed, different (non-free) distros targeting different boards do it in many different ways...FIXME: introduce an easy way as an example.

If things go well, you will see that when you compile u-boot, no non-free blobs are needed, and it should just work with linux-libre. That's how you know your board doesn't need non-free blobs. (Some rockchip boards unfortunately require u-boot to be compiled with a non-free blob inserted, but still work with linux-libre)

Inspired by ryry and del111 I searched for more information and found a website that installs debian using the proposed method: https://www.irif.fr/en/users/letouzey/lime2

So I tried installing trisquel following the instruction, changing the command of dedbootstrap to use aramo and trisquel mirror.

The problem I had was that flash-kernel installation gave an error:

---
Setting up flash-kernel (3.104ubuntu9) ...

Creating config file /etc/default/flash-kernel with new version
grep: /proc/cpuinfo: No such file or directory
flash-kernel: deferring update (trigger activated)
Setting up ssh (1:8.9p1-3+11.0trisquel2) ...
Processing triggers for libc-bin (2.35-0ubuntu3.1+11.0trisquel1) ...
Processing triggers for initramfs-tools (0.140ubuntu13) ...
Processing triggers for flash-kernel (3.104ubuntu9) ...
grep: /proc/cpuinfo: No such file or directory
Can't find /boot/vmlinuz- (see /tmp/flash-kernel-no-kernel-error.log)
dpkg: error processing package flash-kernel (--configure):
installed flash-kernel package post-installation script subprocess returned err
or exit status 1
Errors were encountered while processing:
flash-kernel
E: Sub-process /usr/bin/dpkg returned an error code (1)
---

I continued the installation and right after kernel install (linux-image-generic) again I got complains about flash-kernel:
---
Processing triggers for flash-kernel (3.104ubuntu9) ...
Unsupported platform '"Olimex A20-OLinuXino-LIME2"'.
dpkg: error processing package flash-kernel (--configure):
installed flash-kernel package post-installation script subprocess returned error exit status 1
Processing triggers for linux-image-5.15.0-58-generic (5.15.0-58.64+11.0trisquel13) ...
/etc/kernel/postinst.d/initramfs-tools:
update-initramfs: Generating /boot/initrd.img-5.15.0-58-generic
W: Couldn't identify type of root file system for fsck hook
flash-kernel: deferring update (trigger activated)
/etc/kernel/postinst.d/zz-flash-kernel:
flash-kernel: deferring update (trigger activated)
Errors were encountered while processing:
flash-kernel
E: Sub-process /usr/bin/dpkg returned an error code (1
---

Inserting the sdcard (and a USB Serial Cable to get the output) *didn't* booted.

After that I used the debian's u-boot as suggested by avron from https://wiki.debian.org/InstallingDebianOn/Allwinner#Olimex_A20-OLinuXino-LIME2__rev._F_and_newer_and_Debian11.2F_bullseye_kernel but that didn't work either.

Is the flash-kernel the no-go in this situtation?

Hi nparafe,

I'd say it depends on how flash kernel failed, but either way the stock trisquel kernel doesn't have sunxi enabled, so doesn't boot. In order to get things working (or at least to the next stage) you will likley need to use the FSFLA's freesh repo using this guide here https://www.fsfla.org/ikiwiki/selibre/linux-libre/freesh.en.html. The current lts (6.6) kernel has sunxi enabled at build time, which is what I am using to power my trisquel arm devices kernelwise.

After that, I had to remove flash kernel and the trisquel kernel packages (the trisquel kernel package depends on flash kernel) as it always errored due to the path not being correct for finding a dtb, this I copied manually to a directory i created inside /boot as /boot/dtb then pointed to it in the extlinux.conf file. The init image it creates should be the default and symlinked automatically as long as you have installed the kernel from fsfla freesh and then removed the stock one.

Hope this helps/makes sense

Ryan :)

1. Install necessary packages:
$apt-get install binfmt-support qemu-user-static

2. Prepare sdcard:
cfdisk /dev/sdb

$fdisk -l /dev/sdb
Disk /dev/sdb: 7,49 GiB, 8044675072 bytes, 15712256 sectors
Disk model: R5U880FlashMedia
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: 0x5452574f

Device Boot Start End Sectors Size Id Type
/dev/sdb1 * 2048 501759 499712 244M 83 Linu
/dev/sdb2 501760 15712255 15210496 7,3G 83 Linu

3. Refresh the partition table and format these new partitions:
$partprobe /dev/sdb
$mkfs.ext3 /dev/sdb1
$mkfs.ext4 /dev/sdb2

4.Mount these partitions:
$mount /dev/sdb2 /mnt
$mkdir /mnt/boot
$mount /dev/sdb1 /mnt/boot

5.Debootstrap, part 1
$debootstrap --arch=armhf --foreign aramo /mnt https://mirror.librelabucm.org/trisquel/

6. Debootstrap, part 2
$export DEBIAN_FRONTEND=noninteractive
$export DEBCONF_NONINTERACTIVE_SEEN=true
$export LC_ALL=C
$cp /usr/bin/qemu-arm-static /mnt/usr/bin
$chroot /mnt /debootstrap/debootstrap --second-stage
$chroot /mnt dpkg --configure -a

7. Install linux-libre
$chroot /mnt

$wget https://linux-libre.fsfla.org/pub/linux-libre/freesh/pool/main/f/freesh-archive-keyring/freesh-archive-keyring_1.1_all.deb

$dpkg -i freesh-archive-keyring_1.1_all.deb

$apt install linux-libre-lts

$exit

8. Set root password and hostname

$chroot /mnt passwd

$nano /mnt/etc/hostname

9. Network

$nano /mnt/etc/network/interfaces

auto eth0
allow-hotplug eth0
iface eth0 inet dhcp
iface eth0 inet6 auto

10. edit /mnt/etc/fstab

$nano /mnt/etc/fstab

/dev/mmcblk0p2 / ext4 defaults 0 1
/dev/mmcblk0p1 /boot ext3 defaults 0 2
proc /proc proc defaults 0 0

11. o avoid errors during the final build of the initrd (?):

$mknod /mnt/dev/mmcblk0 b 179 0
$mknod /mnt/dev/mmcblk0p1 b 179 1
$mknod /mnt/dev/mmcblk0p2 b 179 2

12. I suspect this is what ryry proposed:
$cp /mnt/usr/lib/linux-image-6.6.40-gnu/* /mnt/boot/dtb

$mkdir /mnt/boot/extlinux

$nano /mnt/boot/extlinux/extlinux.conf

PROMPT 1
TIMEOUT 50
DEFAULT linux-libre

LABEL linux-libre
KERNEL /boot/vmlinuz
FDTDIR /boot/dtb
INITRD /boot/initrd.img
APPEND root=/dev/mmcblk0p1 rootfstype=ext4 rw video=mxcfb0:dev=hdmi,1920x1080M@60,if=RGB24,bpp=32 console=ttymxc0,115200n8 console=tty1 consoleblank=0

13. Install the u-boot loader which I created using the instructions at https://wiki.debian.org/InstallingDebianOn/Allwinner#Olimex_A20-OLinuXino-LIME2__rev._F_and_newer_and_Debian11.2F_bullseye_kernel:

14.Install the u-boot loader which I created using the instrucrtions at https://wiki.debian.org/InstallingDebianOn/Allwinner#Olimex_A20-OLinuXino-LIME2__rev._F_and_newer_and_Debian11.2F_bullseye_kernel :

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

Hi,

I want to point out some things that were not done correctly in your steps of installation.

> 3. Refresh the partition table and format these new partitions:

Like Ryan and I said, since u-boot supports booting from an ext4 partition, there is no need to make a separate partition for /boot.

> 5.Debootstrap, part 1
> $debootstrap --arch=armhf --foreign aramo /mnt https://mirror.librelabucm.org/trisquel/

There is no need for "--foreign". You only need to install the trisquel package "qemu-user-static", and the second step of debootstrap won't be needed.

> 7. Install linux-libre
> $chroot /mnt

Unfortunately, since you didn't mount /dev, /sys, /proc, initramfs-tool will likely fail. The kernel would simply not boot, no matter what version you install. I did provide instructions for mounting a working chroot:

mount --bind /dev /mnt/dev
mount -t proc proc /mnt/proc
mount -t sysfs sysfs /mnt/sys
mount -t tmpfs tmpfs /mnt/tmp # optional
chroot /mnt

Then you can try installing any version of kernel. It should just work.

> 12. I suspect this is what ryry proposed:
> $cp /mnt/usr/lib/linux-image-6.6.40-gnu/* /mnt/boot/dtb

Yes! You could write a hook under /etc/kernel/postinst.d/ so that the dtbs gets copied on every kernel update.

On extlinux.conf:
> KERNEL /boot/vmlinuz
> INITRD /boot/initrd.img

On trisquel it's more customary to use /vmlinuz and /initrd.img, instead of /boot/vmlinuz and /boot/initrd.img, since /vmlinuz is a symlink to the actual kernel image like /boot/vmlinuz-6.6.40-arm64, but should check if these two files actually exist under /boot or /.

About the kernel parameters:

Like Ryan said, it's better to use partition UUID instead of /dev/sdx... you can check UUID using "blkid".
Also, "rootfstype=ext4" should not be needed. It's also perfectly fine to use "ro" instead of "rw" on kernel parameters. The init system (systemd) will remount the root partition in rw anyway.

> So the Kernel now boots, which is a progress but still no boot.

That's actually only the u-boot output. Linux is not booted yet.