

# Step 
### 1. First, you need to update the ESP32's built-in firmware, open the `UpdateFirmware` example, compile and burn it into the board. 

### 2. Unzip `SIM800_Series_download_Tools_Customer_v1.23.rar` 

### 3. Open `Flash_tool.exe`
![](image/1.png)

### 4. Select the relative firmware and port according to the diagram 
![](image/2.png)

### 5. Wait for the board indicator to light up, then click the `Start Download` button, and wait for it to finish 
![](image/3.png)

# Firmware Link
- [Flash Tools](https://1drv.ms/u/s!AmbpOqVezk5drRlUsrka6VY5OJds?e=daUEOB)
- [SIM800L FW](https://1drv.ms/u/s!AmbpOqVezk5drRsAB6lqCZs4HvWR?e=iujjDh)
- [SIM800C FW](https://1drv.ms/u/s!AmbpOqVezk5drRosZ9mXFF-RqYbj?e=i4Wld8)




