I hope that Ubuntu MATE on the Pi will use the linux-raspi2 kernel in the future instead of the Raspbian kernel. That way, you would have a 32-bit userland and kernel, and you could then install linux-raspi2:arm64 to enable support for 64-bit applications.
Does anyone know how exactly the Xubuntu, Lubuntu, and Ubuntu MATE images were setup so that on first boot, setup loads and lets you create your own user account? On my Debian ARM64 images, there’s already a default username and password, like on Raspbian Lite and older releases of Raspbian.
They just mimic an oem install. oem-config is part of ubiquity (the ubuntu installer). For pre-installed images there is a package jasper (jasper-initramfs) that also used to be used with oem-config, but that doesn’t seem to be used anymore. All are ubuntu packages, not sure if Debian has an equivalent in their repos.
Try an oem install from a ubuntu server image to figure out how it works.
Ubuntu 18.04 has always been usable on the 3B+. An official image may not be available, but the wiki has carried instructions from release on how to boot the server image on a 3B/3B+. I don’t think these are hard to follow or overly long. Please edit the wiki if you can improve the instructions.
A couple of weeks later I made available unofficial xubuntu 18.04 arm64/armhf installers/images for the pi series. These are free to download and use.
Note, the pi foundation is very hostile to any distro that is not Raspbian. They upstream little and at a glacial pace. There is little incentive for distros to work on pi images.
I’d love to help make images, but I had an annoying issue when creating an Ubuntu image with debootstrap. I installed a minimal Ubuntu base using debootstrap, but when I tried to restart dbus, it hung on “Starting system message bus”. /proc, /dev, /dev/pts, and /sys were all mounted.
I’ve never build an image from the ground up. I’ve always used the build system that ubuntu uses to make the official images. I posted the scripts earlier.
You just need to edit ‘build-pi-iso’ and change xubuntu to ‘ubuntu-mate’. Run it and it will make the squashfs filesystem, before erroring out at syslinux (iso bootloader). Make whatever changes to ‘complete-iso’ and run it. You’ve then got a ‘live/desktop’ installer.
Still building the image at the moment. The Ubuntu MATE desktop (ubuntu-mate-desktop) has downloaded and is currently unpacking. I hope I’ll be able to release this image at some point for those willing to test. I’ve updated the bootloader files (bootcode.bin, *.dat, *.elf) to make sure that the image works on the latest Pi models.
I’ve noticed a couple of inaccuracies on your GitHub ‘readme’ page though…
Linux-raspi2 receives regular updates and has support for the 3B+. In fact I think the updates are going to cause you problems with your choice of raspi3-firmware package (see comments in bug reports).
3D accelerated graphics should be available via an overlay. It certainly works on armhf with Linux-raspi2. Ubuntu-core boots with this turned on.
linux-raspi2 in bionic is stuck at 4.15 which reached EOL in April. I doubt this kernel has support for the 3B+ either. To fix this problem in my Ubuntu MATE 18.04 image, I had to update the bootloader by following the instructions on the Ubuntu Wiki.
Cosmic, on the other hand, has a newer linux-raspi2 kernel (4.18).