You have your Raspberry Pi ready. It is connected to the monitor, the power cable is connected correctly and you have already flashed Raspbian (or other operating system) to a microSD card.
But something is wrong. Perhaps the Pi stopped by booting onto the Rainbow. Maybe it’s stuck in the boot loop. Or maybe your problem is something else. Whether you’re trying to resolve issues with your Raspberry Pi’s ability to connect to Wi-Fi, detect a USB device, install software, or access a microSD card, we’ve got a suite of solutions right here.
1. Your Raspberry Pi is hanging on a rainbow screen
When you boot up your Raspberry Pi, the first thing you’ll see (unless you’re preparing to install with NOOBS. with software) is the GPU test screen. This is commonly known as the «rainbow screen» and should appear in just a couple of seconds. After that, the operating system should boot.
However, sometimes this does not happen. Instead, the device will freeze when testing the GPU. If this happens, you have a problem.
In most cases, this is due to an issue with the Raspbian kernel image on your microSD card. To test, install Raspbian on another microSD card and boot from it. If it works, then the problem is with the original microSD card.
However, it’s not ideal. In addition, you may have the necessary data from the original microSD card. To get this data, insert a microSD card into your computer’s card reader. Go to folder /home/ and copy it to your computer’s hard drive.
Can you fix the core?
It is possible under certain circumstances to restore the kernel, but this requires the Pi to be connected via Ethernet to your network. You will need to connect via SSH. so make sure this has been enabled beforehand. If not, when the microSD card is connected to your computer, add the file to the directory /boot/s named ssh. Do not include the file extension.
Using your preferred SSH client, connect to the Pi using the IP address and your normal username and password. Then try to reinstall the kernel:
sudo apt update sudo apt install raspberrypi-kernel
Wait until this completes, then open the config.txt file in a text editor:
sudo nano /boot/config.txt
Add a new line here:
boot_delay=1
This download delay forces the Pi to give the SD card time to prepare before booting from it.
Click ctrl+X, to exit then Y and enter, to save changes and exit the text editor. Use the reboot command to restart the Pi. If it freezes again while testing the GPU, it’s time to use another microSD card.
SD card maintenance
If you’re worried about your Pi’s microSD card, it’s worth looking into ways to extend its lifespan. You can do this by either making sure more data is written to RAM (not the microSD card) or bypassing this entirely with a USB device.
Cloning your microSD card is also possible. about the integrity of data across multiple cards or devices.
2. Unable to detect USB device? Try it
All USB devices are essential for using the Raspberry Pi. Whether you want to connect an input device (mouse, keyboard, game controller) or expand your computer’s functionality, many options are available via USB. Using an old Pi without built-in wireless or Bluetooth? You will need a USB key.
Often, connecting a device allows you to use it almost immediately. But what if your USB device is not recognized?
The first thing to do is go to the list of verified peripherals on eLinux.org. Search page for your USB device; if it’s here, it should work.
Then check if the device works on another computer. Connect it to your PC; is it working right? Once you’ve done that, it’s time to interrogate the Raspberry Pi and the USB device. On your Raspberry Pi, enter:
sudo dmesg -C
Then insert the USB device and type:
dmesg
If detected, your USB device will be displayed here along with any error message. If the device is not listed, there are two main reasons:
- Faulty USB device or USB Pi bus.
- Your Raspberry Pi is not getting enough power.
Overcome the last problem by purchasing a suitable power supply for your Raspberry Pi or a powered USB hub. USB device detected but nothing happens? Try updating the repositories and checking for updates (a fix for many Raspberry Pi issues):
sudo apt update sudo apt upgrade
At this point, you should have a working device. If not, contact the manufacturer and see if there is a driver for Linux.
3. Easily surf the Internet using Wi-Fi
If you are using a Raspberry Pi 3 or Pi Zero W or later, then your computer has built-in Wi-Fi. You can also provide a wireless connection to an old Pi using a Wi-Fi dongle. But once you activate your wireless network, how do you access the internet?
USB flash drives can be a problem, as noted above. But if you’ve followed the tips above and confirmed that the device is working, then the network connection issue might be related to the setup. Let’s assume that at this stage you tried to connect to the wireless network through the desktop.
So, what can stop you from connecting your Raspberry Pi to a wireless network? First, there is a possibility that new connections are blocked or the limit has been reached. Once you can rule this out, try connecting to a different network. For example, you can set up a wireless hotspot on your phone and see if you can connect to it.
There is also the possibility that your credentials are incorrect. It happens. To double check open the file wpa_supplicant.conf in nano:
sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
Here you will find the key settings for connecting to your network. Use margins SSID and PSK, to enter the correct SSID (network name) and password.
Or check the security of your network. The Raspberry Pi 3 will not connect to wireless networks that are secured using the legacy Wireless Encryption Protocol (WEP). If your router uses this, switch to WPA, WPA2, or if that’s not possible, upgrade to a new router.
4. Problem with your Pi’s display
Several issues can affect the display of your Raspberry Pi.
Although the default resolution is 800×400 pixels, most modern monitors and TVs have much higher resolutions. What should happen is that the display size is determined when the Pi boots up and the desktop resolution is adjusted accordingly.
Sometimes this does not happen, resulting in some parts of the screen not being visible. Most of these problems can be fixed in the file config.txt . Because this is an important file, it’s very important that you don’t make any changes that might cause problems. To protect yourself from this, make a copy of the file with a slightly different filename:
sudo mv /boot/config.txt /boot/config-orig.txt
If you run into problems at any point, just delete the config.txt file and rename the copy.
When you’re ready, edit config.txt file in nano:
sudo nano /boot/config.txt
Many display problems come down to misapplied scan settings. Typically, a black bar borders the screen, much like an 8-bit home computer display. You can change this by looking at the config.txt file and finding:
#disable_overscan=1
Remove hash character; this will «uncomment» the setting, meaning it will be applied. Click ctrl+X, then Y, to save and exit, and reboot the Pi.
