Using FIT Images as artifacts

General Discussions
1

Hi,

We are thinking of using Mender on a project we are currently undertaking after using it successfully in a couple of previous projects. The board has a MediaTek MT7688AN SoC which has a MIPS processor. It has a very small NOR flash (64MiB) but has a relatively large amount of DDR memory (128MiB) so we are thinking of deploying FIT images containing the kernel, device tree and an initramfs that will stay resident in memory directly to a raw partition in the NOR. From what I’ve read and from previous usage of Mender I think it will support FIT images as deployable artifacts but just wanted to check.

I was also wondering if there are any known problems with using MIPS?

And a last question is does mender provide any support for splitting the data partition out of the rootfs into another filesystem such as a UBIFS within the Yocto framework? I know this is Yocto related but if Mender already has some classes to do this then that would be great otherwise I’m happy to do this within our Yocto build.

Cheers,
Martin.

2

Hi Martin,

I have not personally worked with FIT images so I can’t comment specifically but with the update module framework you can likely implement whatever custom update method you like.

I’m unaware of any issues with MIPS. Please let us know how it goes.

As for the data partition, if I am understanding what you are trying to do correctly, you can specify the fstype of the data partition using the MENDER_DATA_PART_FSTYPE variable, and then added “dating” to IMAGE_FSTYPES to have that partition image created in a separate file.

Drew

3

I’ve think I’ve done essentially what you’re proposing (though on ARM) where my NOR storage contains:

Bootloader
RootfsA - fitImage containing kernel, device tree and squashfs initramfs
RootfsB - fitImage containing kernel, device tree and squashfs initramfs
Data

It works well but there were some patches required to both the Mender client code and the Mender uboot code to facilitate loading fitImages and having a rootfs mounted in RAM. There’s some info in some of my previous posts: Read only compressed rootfs in raw flash?, Updating when rootfs is in RAM? and Xilinx Zynq - change mender to have rootfs inside fit image.

As Drew said, it might be easier to use update modules but thought it was worth sharing in case it helps!

4

Thank you for all of your replies, I’m going to start integrating Mender today and the information here has been really useful. I’ll let you know how I get on.

Many Thanks,
Martin.