## Using GDB stub

- Add `#include <GDBStub.h>` to the sketch
- Upload the sketch
- Redirect serial port to TCP port:
```
    tcp_serial_redirect.py -p /dev/tty.SLAB_USBtoUART -b 115200 --spy -P 9980 --rts=0 --dtr=0
```
Change port and baud rate as necessary. This command requires python and pyserial.
- Observe serial output:
```
    nc localhost 9980
```
- Once crash happens, close nc and start gdb:
```
    xtensa-lx106-elf-gdb /path/to/Sketch.cpp.elf -ex "target remote :9980"
```
Or, using the provided gdbcmds file:
```
    xtensa-lx106-elf-gdb /path/to/Sketch.cpp.elf -x gdbcmds
```
- Use gdb to inspect program state at the point of an exception.

## Tips and tricks

- To halt the target when software WDT fires, add
```
    ((int*)0) = 0;
```
at the top of `__wrap_system_restart_local` in core_esp8266_postmortem.c.

## License

Espressif MIT License. See License file.