Debian buster should be able to run on all of the Raspberry Pi ≤3 models, but there are a few issues preventing us from releasing an official image:

Longer-term improvements:

Any help on these issues is very welcome!

Preview images

First, lets set up some environment variables matching your needs. First, the raspberry model — It can currently be 0w, 2 or 3. If it's a 0w:

$ export RPI_MODEL=0w

Second, where is your SD card detected in your computer? Lets say, it's /dev/sdf:

$ export SD_CARD=/dev/sdf

Now, get the image you need:

$ wget https://people.debian.org/~gwolf/raspberrypi/20190628/20190628_raspberry-pi-${RPI_MODEL}_buster_PREVIEW.img.xz

It is recommended to check the image was correctly downloaded by comparing its SHA256:

$ wget https://people.debian.org/~gwolf/raspberrypi/20190628/20190628_raspberry-pi-${RPI_MODEL}_buster_PREVIEW.img.xz.sha256
$ sha256sum -c 20190628_raspberry-pi-${RPI_MODEL}_buster_PREVIEW.img.xz.sha256
20190628_raspberry-pi-0w_buster_PREVIEW.img.xz: OK

Now, write the image to your SD card! Make sure $SD_CARD is right! (you risk losing information otherwise!)

$ xzcat 20190628_raspberry-pi-${RPI_MODEL}_buster_PREVIEW.img.xz | dd of=${SD_CARD} bs=64k oflag=dsync status=progress

If resolving client-supplied DHCP hostnames works in your wired network, you should be able to log into the Raspberry Pi using SSH after booting it (otherwise, you can only log in from the console):

$ ssh root@rpi3
# Password is “raspberry”

Of course, we want to come up with a better way to do this than shipping a network-listening service with a preset root password :-Þ

For the sources of this image (and/or for customizing your own build), please see https://salsa.debian.org/raspi-team/image-specs

Installation

It’s not necessary to dump a prebuilt image onto the SD card. You can use the configurable builder used to create the images linked above or a simple shell script creating Raspberry Pi 3B+ arm64 (or armhf) images to create your own image file or install straight to the SD card, from another running GNU/Linux machine.

This avoids problems with things like preset passwords, machine IDs, lack of random bytes/entropy, …