Hass won't boot on RPI3

I just installed a fresh Hass OS on my RPI. When I turn the RPI on nothing happens. I can’t see my RPI in my IP scanner and http://homeassistant.local:8123 doesn’t work either. I have waited for 2 hours. My RPI green light flashes 5 times slow and 3 times fast and then repeats.

I tried it with a fresh re-install of raspberryOS and that just works.

What version of RPi are you using?

I have a raspberry 3 and i used the 32-bit flash file

Are you using an SD card? Were you using the same SD card for the Raspberry OS as for the Home Assistant image?

Did you logged in to your router via the browser and checked whether an ip address for the Raspberry is popping up?

Yeah i am using the same SD and no there is no IP address

Did you actually logged in to your router via the browser?

yess, I did

You double checked whether you have the right image?

Raspberry Pi 3 has a different image than rpi 4.

I tried it with both and both didnt work

hmm, you said I did a fresh installation. Is this the first time you are running Home Assistant on this raspberry pi or did you succeed before?

I had Hass Core installed, but i wanted to be able to install addons so i did a fresh full OS install

Here are some descriptions of LEDs blinking and their meaning: Raspberry Pi Act LED Error Patterns - PiShop.ca Support Portal

Can it be instead of 5 times slow and 3 fast, 4 slow and 4 fast? Then it says unsupported board type.

You can also try an older version of Home Assistant. Maybe HaOS 8 is giving a problem.
You’ll find images of previous releases here: Releases · home-assistant/operating-system · GitHub

And also maybe try another SD card. Is your power supply heavy enough? Did you use a different one this time?

I would recommend an USB connected SSD card anyway, if you want a more durable setup. As SD cards will fail after a certain time.

I think it gives the unsupported board type error. How can I fix that?

I would say that the unsupported board type means that you could have used the wrong version of image for your raspberry. However, you did already check that.

A google pointed me to this: pi 3b+ - Rpi 3B+ "Unsupported board type" Flashing Power Light - Raspberry Pi Stack Exchange

Here is someone reporting this error as a result of the SD card he is using. Maybe try a different SD card.