[yocto] Generation of an image of an edited Ubuntu rootfs

[Stefano Babic]

Hi Albert,

On 23/08/2018 15:42, Albert-Miquel wrote:
> Hello all,
> 
> I'm mainly a VHDL developer, although in our last project I've started
> working with an embedded Linux installed in a ZYNQ from Xilinx that
> combines logic with several processors.
> 
> Due to my lack of knowledge, I started using the rootfs of an embedded
> ubuntu to develop the software (as described here
> <https://medium.com/developments-and-implementations-on-zynq-7000-ap/install-ubuntu-16-04-lts-on-zynq-zc702-using-petalinux-2016-4-e1da902eaff7>),
> since it was easier for me to install the necessary packages, while the
> BOOT and other files were created with Petalinux (I did not know about
> Yocto at the beginning). To sum up, the ZYNQ is running Ubuntu on one of
> the processors (while the baremetal code that controls the firmware is
> run on the other one).

Well, it looks like we are OT here..

> Everything is currently (and temporarily) running
> from the SD card, so that the SD has two partitions, one called BOOT
> (containing the files BOOT.BIN, image.ub and system.dtb), and another
> one with the rootfs tree. I have been working with this scheme for a
> while, installing several packages and developing some applications.
> Thus, rootfs has far evolved from the initial one.
> 
> My intention now is to set SWUpdate
> <https://sbabic.github.io/swupdate/swupdate.html> to remotely update all
> the software everytime a new version is released, so that I should
> generate an image of each of the two partitions. The problem is that I
> do not know which should be the right steps to generate these images. As
> I understood, Yocto can provide a clean rootfs, but I've not been able
> to find the way to integrate your own rootfs.

Considering all of these, it looks like you won't use Yocto. You can
build a debian package from SWUpdate sources (check in debian directory
and in the documentation) and you can add it to your rootfs.

> Considering the situation
> described here, is there any tutorial/web/anything that could be used as
> a guide (for dummies) to suitable generate the images using Yocto? Any
> help will be greatly welcome.

Image generation is supported via the additional meta-swupdate layer,
but this works until you are in a OE environment. Outside this, you have
to generate images on your own.

Example how to build the image is here:

http://sbabic.github.io/swupdate/swupdate.html#building-a-single-image

Best regards,
Stefano Babic

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