I have bought a rpi4 model b 4GB, I put image hassos_rpi4-5.9.img on a 32SD, rpi4 connected LAN.
I have try 3 different SD.
connecting via browser to homeassistant.local:8123 I can see a page “Preparing Home Assistant”… more than 20 hours and the page say always “Preparing Home Assistant”.
I have try for several day… never complete first installation
what’s wrong? My new rpi4 ?
I had the same (with RPI 3) and never got it fully to work either.
If you press the blue ‘button’ of the installation you will see where it is hanging.
I either had issues downloading files from a repo or with communication with my internal docker
Make sure you have pi-hole disabled during install (if you are running this). Sides by that I can’t offer much advice. Glad i am not alone with this issue 
20-12-21 18:42:56 WARNING (MainThread) [supervisor.homeassistant.core] Error on Home Assistant installation. Retry in 30sec
20-12-21 18:43:26 INFO (SyncWorker_0) [supervisor.docker.interface] Updating image homeassistant/raspberrypi4-homeassistant:landingpage to homeassistant/raspberrypi4-homeassistant:2020.12.1
20-12-21 18:43:26 INFO (SyncWorker_0) [supervisor.docker.interface] Downloading docker image homeassistant/raspberrypi4-homeassistant with tag 2020.12.1.
20-12-21 18:43:41 ERROR (SyncWorker_0) [supervisor.docker.interface] Can't install homeassistant/raspberrypi4-homeassistant:2020.12.1 -> 500 Server Error for http+docker://localhost/v1.40/images/create?tag=2020.12.1&fromImage=homeassistant%2Fraspberrypi4-homeassistant: Internal Server Error ("Get "https://registry-1.docker.io/v2/": net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)").
20-12-21 18:43:41 WARNING (MainThread) [supervisor.homeassistant.core] Error on Home Assistant installation. Retry in 30sec
20-12-21 18:44:11 INFO (SyncWorker_0) [supervisor.docker.interface] Updating image homeassistant/raspberrypi4-homeassistant:landingpage to homeassistant/raspberrypi4-homeassistant:2020.12.1
20-12-21 18:44:11 INFO (SyncWorker_0) [supervisor.docker.interface] Downloading docker image homeassistant/raspberrypi4-homeassistant with tag 2020.12.1.
20-12-21 18:44:26 ERROR (SyncWorker_0) [supervisor.docker.interface] Can't install homeassistant/raspberrypi4-homeassistant:2020.12.1 -> 500 Server Error for http+docker://localhost/v1.40/images/create?tag=2020.12.1&fromImage=homeassistant%2Fraspberrypi4-homeassistant: Internal Server Error ("Get "https://registry-1.docker.io/v2/": net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)").
20-12-21 18:44:26 WARNING (MainThread) [supervisor.homeassistant.core] Error on Home Assistant installation. Retry in 30sec
500 Server Error ??
I guess my reply won’t help you, but the issue I have, is the same. After waiting A LONG time it would sometimes boot till the setup phase. Then it was still barely usable because I cannot install any addons nor update it.
I got my device installed after at least 10 attempts. Sometimes rebooting it (many times) got me to this point.
I found also here https://github.com/home-assistant/operating-system/issues/1108#issuecomment-748860773 same problem.
in that topic the scenario is like me: My network it’s the same!
could be a MTU issue ?
I have to try an installation LAN cabled to my modem directly
Checked the github post, but it doesn’t really give me any clues. Will read it tomorrow again.
My network setup is different, but issue is same. Network looks like
Modem - Router -> Raspberry
Also tried Modem -> router -> switch -> raspberry
Only thing I did not try is directly connected to the modem.
BTW: I also have the issue with the developers release image. Tried this version:
hassos_rpi3-6.0.dev20201220.img.xz
Do you have the same?
i spotted the following in the current issues. https://github.com/home-assistant/operating-system/issues/1086
Appears many are having issues with with installation when the install attempts to download and install current version.