I formatted my SD card to fat32 using GParted and copied all the files from the official NOOBS Lite download: https://www.raspberrypi.org/downloads/noobs/. I unzipped using unzip command on the terminal. When I turn on the rainbow appears and the Pi gets stuck there. Red LED is on, green turned off after a few seconds. Don't know if I did something wrong or my card is broken. Appreciate your help.
Feel so dumb. Tried connecting to the other HDMI port and the image appeared, it was actually booting but showing the rainbow through that port. How do I switch from HDMI port 1 to 2 to show as default? I have to force it a little to use HDMI port 1 as it is right next to the power cable. Also, now I'm getting another error when I try to flash Raspbian full:
Error creating file system Mkfs.fat: warning lowercase labels might not work properly with DOS or Windows Mkfs.fat: too few blocks for viable system Mkfs.fat: 3.0.26 (2014-03-07)
The Boot Problems Sticky contains detailed troubleshooting steps.
Using NOOBS just makes fault finding harder.
The rainbow screen is due to missing (or obsolete) firmware.
I suggest you use Etcher to install Raspbian to a SD Card (like the vast bulk of us).
If you REALLY want to install NOOBS, make sure you have the LATEST version and follow the Foundation instructions =>
Visit the SD Association’s website and download SD Formatter for Windows or Mac.
I ran into the same problem while working on my project. It seems like a low voltage problem so make sure the power supply has minimum of 2A Output and that should fix the rainbow screen problem.