Overview
Is your Raspberry Pi Zero or Zero W not booting? Try these troubleshooting steps before contacting support.
Most Pi Zero boot issues are caused by SD card problems or insufficient power.
Reinsert and reflash SD card
Step 1: Re-seat the SD card
- Unplug the device
- Remove the SD card
- Reinsert the card: Push it all the way in until it clicks - the Pi Zero's card slot is spring-loaded
- Power on and test
Step 2: Reflash the SD card
If the SD card is corrupt or improperly flashed, the Pi cannot boot. The LED indicators will tell you if this is the problem.
- Download Raspberry Pi Imager: Get it from raspberrypi.com/software
- Write fresh OS: Use Raspberry Pi Imager to write Raspberry Pi OS to the SD card
- Eject safely and insert into Pi Zero
- Power on and test
See: raspberrypi.org/documentation/installation/installing-images
Check power supply
The Pi Zero requires adequate power:
- Minimum requirement: 5V 2.5A power supply recommended
- Micro USB power: Pi Zero uses micro USB for power (not mini USB)
- Try different supply: If you have a Vilros power supply designed for Pi Zero, try flipping the switch a few times and reinserting it
- Test with phone charger: Some cell phone power supplies work - use one rated at least 2A
Signs of power problems:
- Rainbow square in corner of screen (if connected to display)
- Random reboots or freezes
- Red LED flickers instead of staying solid
Check LED indicators
The Pi Zero LEDs tell you what's happening:
- Power on the Pi Zero with SD card inserted
- Observe the LEDs
Normal LED behavior:
- Red LED: Should turn on and stay solid (power indicator)
- Green LED: Should flash periodically (SD card activity)
Abnormal LED behavior indicates problems:
- Green never flashes: Pi cannot read the SD card - card is corrupt or not properly flashed
- Green flashes rapidly and continuously: SD card read error - reflash the card
- No red LED: No power reaching the Pi - check power supply and cable
- Red LED flickers: Insufficient or unstable power
If you do not see the green light at all, or if it flashes repeatedly without staying on for more than a second, the SD card is faulty and needs to be reflashed.
Further help
If you've tried these steps and your Pi Zero still won't boot:
- Try a different SD card: Test with a known-good SD card to rule out card failure
- Check for physical damage: Inspect the micro USB port and SD card slot
- Test display output: If using mini HDMI, make sure the cable is firmly connected
- See also: Raspberry Pi Pico basics if you need a simpler board