Stuck at Rainbow-Screen

Hi, I just bought the new essential kit (the new 3B+) and can’t seem to boot.
I am always stuck at the rainbow screen with a white flah icon in the top right corner.
The pwr led blinks 4 times slow, then 3 times fast, then stays on for 2 seconds before going blinking again.

I have tried formatting the SD card several times, copied noobs/pinn files on it. Even used etcher to write an OS (retropie) on it. Always the same outcome.

Any ideas?
Thank you for the help!

Is that the very latest - 2.7.0 - version of NOOBS? From here https://www.raspberrypi.org/downloads/noobs/

Do you have another Pi to test your SD card in? Or another SD card to try? If you run sudo apt-get update, and then sudo apt-get upgrade, from terminal on another Pi, the SD card should then be bootable on a 3B+ and be transferable to a 3B+.

I used another SD Card and can now boot into PINN. Installed retropie and libeelec. The latter booting fine, but retropie just shows a black screen.

Any ideas on how to get into retropie?

Thank you so much!

Best guess is retropie haven’t updated their boot code for the B+ yet.

You are correct. A newer beta installation is working now.
Thanks guys.

That’s good to hear, have fun with your new Pi.