When you boot your Raspberry Pi, the first thing you’ll see (unless you’re prepping an installation with NOOBS) is the GPU test screen. This is commonly known as the “rainbow screen” and is intended to appear for just a couple of seconds. After this, the operating system should load.
However, sometimes this doesn’t happen. Instead, the device will hang at the GPU test. If this occurs, you have a problem.
common raspberry pi issues and fixes
In most cases, this is due to a problem with the Raspbian kernel image on your microSD card. To test, install Raspbian onto another microSD card, and boot from this instead. If it works, then you know the problem is with the original microSD card.
However, it’s not ideal. Additionally, you may have data you need from the original microSD card. In order to retrieve this data, insert the microSD card into your computer’s card reader. Browse to the /home/ folder, then copy it to your PC’s hard disk drive.
Regards,
Rachel Gomez