Many of us will have the experience of putting together a build only to have nothing happen. It’s confusing and frustrating even when you are trying to keep your mind open and learn as you go. Every mistake is a learning experience and all that but at the same time it would be nice if things just WORKED! Thankfully Raspberry Pi’s have built in error code LED patterns that help show what could be going wrong during a build.
While booting up your Raspberry Pi the green ACT LED might start flashing but nothing is happening on your build. This is a sign that something isn’t quite right and you should start counting the blinks. Here are some of the common issues that the board might be trying to signal for you:
These patterns apply to all except the Raspberry Pi 4
It is also important to remember that 4 flashes can also mean a broken SD card connector. When 1 Databit is connected but any of the other 3 don’t make contact the SD card only works in 1-bit mode which will give you a 4 blinks error. Make sure all the pins make contact with the card.
Another thing to try going right back down to the basics! Disconnect anything extra and boot up the board using only the video and power cables. You will also need a really basic USB keyboard to be able to switch video modes.
Raspberry Pi 4 Troubleshooting
The Raspberry Pi 4 works differently than previous versions which means the blink patterns are also different and indicate different things. The boot up is more complex and has more features, so if it doesn’t find a valid start.elf file on the SD card it will blink the LED four times with an interval between the four blinks. Which means unlike the older boards it won’t mean that the SD card is booting, it means the code can’t find the SD Card at all.
Following this there are a series of LED warning codes that a Raspberry Pi will show you. The LED will blink in long and short flashes with a 2-second gap separating the loop. Here are a series of loops that might occur:
|
Long flashes |
Short flashes |
Status |
|
0 |
3 |
Generic failure to boot |
|
0 |
4 |
start*.elf not found |
|
0 |
7 |
Kernel image not found |
|
0 |
8 |
SDRAM failure |
|
0 |
9 |
Insufficient SDRAM |
|
0 |
10 |
In HALT state |
|
2 |
1 |
Partition not FAT |
|
2 |
2 |
Failed to read from partition |
|
2 |
3 |
Extended partition not FAT |
|
2 |
4 |
File signature/hash mismatch - Pi 4 |
|
4 |
4 |
Unsupported board type |
|
4 |
5 |
Fatal firmware error |
|
4 |
6 |
Power failure type A |
|
4 |
7 |
Power failure type B |
Conclusion being: if the ACT LED blinks in a regular four blink pattern, it cannot find bootcode (start.elf). If the ACT LED blinks in an irregular pattern, then booting has started. If the ACT LED doesn't blink, then the EEPROM code might be corrupted. Try again without anything connected to make sure.
Now hopefully this can make us all able to get our projects working with minimal stress!
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