I have a Raspberry Pi 4 with NOOBS. When I try to boot NOOBS it shows the rainbow screen and then freezes. I have limited the possible reasons why it won't boot to either my 32GB card is not formatted correctly or that my Raspberry Pi is broken. So, I am asking "Does NOOBS showing/freezing on the Rainbow screen mean that the microSD card reader is working?".
If you think you can fix my Rainbow screen problem please see this question.