HA Yellow installation problems

Hi, I recently purchased a HA Yellow kit (rev. 1.3 - not PoE) with a standard CM4 module pre-installed. I started up with the getting started guide, not knowing that the CM4 module probably already had HA installed on it. I installed my NVME SSD (970 EVO+), everything was going good.

However, when I attempted to boot from a USB stick, with the HA yellow image it never seemed to work. After 12+ hours it was still blinking steadily green and yellow, up until I powered it off. I read through the getting started guide again, and found that the yellow led should blink constantly for 5 seconds to show that the installer is ready. This never happend when I tried the USB-stick installer again. I checked, that the ethernet port seemed to have contact with the PI. The SSD got removed to reduce the potential causes for errors.

I then tried both “Resetting a Device” and “Reinstalling the Operating System” through the buttons to no luck. Lastly, I tried the reinstall using the rpiboot. This did however not seem to work either.

I am however not stuck with a HA Yellow which completely ignores anything I do. It just starts up with both the red and green LED’s permanently on. Buttons does not do anything and running the rpiboot does not seems to work properly? (see snippet below)

I am completely new to Home Assistant and Raspberry Pi’s in general, so my apologies for my ignorance.

Any input as to what I can do to fix the problem? Thank you in advance!