Variscite DART-6UL with Ubuntu Core?

Has anyone successfully built an Ubuntu Core image for the Variscite DART-6UL? It uses an i.MX-6UL processor, so I’d thought it might not be too hard to get going based on @ogra’s guide at - but I’m having some real problems.

Firstly, Variscite have their own fork of u-boot and it seems like they haven’t merged back into the upstream for a while. I tried making changes to use FAT instead of MMC for the config, and eventually found I needed to use an older 2015 version of u-boot to be able to make the changes in the config and have them compile.

For reference, this is where I’m up to with the gadget snap config:

I’ve also got a kernel snap that I’ve compiled, and I have been able to confirm the kernel build does work - by taking the zImage produced by snapcraft and replacing a working Debian image’s copy with my snapcraft zImage - I believe the kernel snap doesn’t actually use the zImage file, but I take this as confirmation at least that it does work enough to boot because Debian can boot using default Variscite settings and my zImage.

After running through the various snapcraft commands, and making an image with ubuntu-image, and flashing that onto an SD card, I do get some level of boot progress (see attached boot log) - but it crashes not to far in with a kernel panic. Just before that, I can see:

sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
sdhci-pltfm: SDHCI platform and OF driver helper
sdhci-esdhc-imx 2190000.usdhc: Got CD GPIO
mmc0: SDHCI controller on 2190000.usdhc [2190000.usdhc] using ADMA
mmc0: host does not support reading read-only switch, assuming write-enable
mmc1: SDHCI controller on 2194000.usdhc [2194000.usdhc] using ADMA
Unhandled fault: external abort on non-linefetch (0x1008) at 0xa4a80fd4

Does this sound familiar to anyone? What should I be trying next? I’d been able to keep working away and get from zero output at all from my compiled u-boot, to getting to this point where it looks like it’s almost there - but there’s probably something small that I’ve missed.

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Hi @seanlano,

where you able to progress on that matter ? I’m currently in the process of creating an image for the imx8m mini but i don’t really know where to start.

Hey @bsteenput, unfortunately no – I didn’t get it working, and have since moved on to another company so don’t have access to the development kit anymore. :slightly_frowning_face: