Understanding and Fixing ESP32-S2 Mini WiFi Reboot Issues

The ESP32-S2 Mini is a popular IoT development board, but clones often suffer from WiFi-related instability. This article compiles proven solutions from real-world troubleshooting cases to help you resolve reboot and freeze issues.

Common Symptoms of WiFi Instability

Users report these telltale signs of problematic ESP32-S2 Mini clones:

• Random reboots during WiFi operations like scanning networks
• Board freezes that resolve when touching the PCB or antenna
• Works with conductive fixes - temporary stability when placing coins or paperclips on EN/3V3 pads

Root Causes and Permanent Solutions

1. WiFi TX Power Interference (Most Effective Fix)

Discovery:
After extensive testing, users found that:

• Default 20dB TX power causes instability
• Lowering to 18dB provides reliable operation
• 19dB or higher brings back crashes

Implementation:

# ESPHome configuration example
wifi:
  output_power: 18.0dB

Benefits:

• No hardware modifications needed
• Completely resolves reboot issues
• Maintains sufficient WiFi range

2. EN Line Stabilization

For boards still experiencing issues:

Solution	Effectiveness	Notes
10µF capacitor (EN-GND)	Partial	May still have random disconnects
10K resistor (3V3-EN)	Minimal	Doesn't solve core issue
Additional 15nF cap	None	No measurable improvement

Best Practice:

• Always check for existing "C14 capacitor GND fix" (solder blob)
• Combine with TX power adjustment for best results

3. Power Supply Considerations

Critical Checks:

• Verify stable 3.3V output during WiFi transmission
• Use quality USB cables (measure voltage drop under load)
• Minimum 1A power supply recommended

Proper power supply and TX power adjustment solve most ESP32-S2 Mini WiFi issues.

Recommended Troubleshooting Flow

1. First try: Lower WiFi TX power to 18dB
2. If persists: Add 10µF capacitor between EN-GND
3. Final check: Verify power supply stability

For guaranteed-stable ESP32-S2 modules and technical support, contact EBEE at [email protected]. Our engineering team can help select the right components for your application.