Reset serial port of ESP32 / Arduino devices. Can be used to reset a serial port before running esptool.

reset_serial.py

import serial
import time
import sys

import serial.tools.list_ports

ports = serial.tools.list_ports.comports()

print("Current serial ports:\n")

for port, desc, hwid in sorted(ports):
    print("{}: {} [{}]".format(port, desc, hwid))

if len(sys.argv) > 1:
    print("\nResetting...\n")
    com = serial.Serial(sys.argv[1], 1200, dsrdtr=True)
    com.dtr = True
    com.write(b"\x00")
    time.sleep(2)

    # This part fails due to the device resetting, but the device is actually reset
    try:
        com.dtr = False
        time.sleep(1)
        com.close()
    except OSError:
        pass

    ports_after = serial.tools.list_ports.comports()

    print("Device's serial port should have been reset:\n")
    for port, desc, hwid in set(ports_after) - set(ports):
        print("{}: {} [{}]".format(port, desc, hwid))

    print(
        "\nUsually the reset device will get a new serial port, make sure to upload using that port."
    )
else:
    print("\nPlease pass the serial port to this script")

Example usage to reset the serial port of a TLora-T3S3 board's serial port:

$ python reset_serial.py /dev/ttyACM0
Current serial ports:

/dev/ttyACM0: LilyGo TLora-T3S3-V1 - TinyUSB CDC [USB VID:PID=303A:1001 SER=AC5495DFA5A3 LOCATION=1-2:1.0]

Resetting...

Device's serial port should have been reset:

/dev/ttyACM1: USB JTAG/serial debug unit [USB VID:PID=303A:1001 SER=AC:54:95:DF:A5:A3 LOCATION=1-2:1.0]

Usually the reset device will get a new serial port, make sure to upload using that port.