I am constantly forgetting where to find the explanation for the ESP32 boot codes. So here’s a handy table:
| Code | Description |
| 0 | No Meaning |
| 1 | Vbat power on reset |
| 2 | ———— |
| 3 | Software reset digital core |
| 4 | Legacy watch dog reset digital core |
| 5 | Deep Sleep reset digital core |
| 6 | Reset by SLC module, reset digital core |
| 7 | Timer Group0 Watch dog reset digital core |
| 8 | Timer Group1 Watch dog reset digital core |
| 9 | RTC Watch dog Reset digital core |
| 10 | Instrusion tested to reset CPU |
| 11 | Time Group reset CPU |
| 12 | Software reset CPU |
| 13 | RTC Watch dog Reset CPU |
| 14 | for APP CPU, reset by PRO CPU |
| 15 | Brownout detected: Reset when the vdd voltage is not stable |
| 16 | RTC Watch dog reset digital core and rtc module |