Printer A20M no longer responds after upgrade

[JuMe]

I tried to upgrade my A20M from Marlin 1.1.8 via Cura with a hex file to 1.1.8 with 3D touch. The board is GT2560 V31.1, the upgrade was not accepted, but the printer doesn't respond anymore. The display is on, but no display. A reset does not work. The COM3 interface is okay on the PC side, but the printer cannot be connected to the PC. I have tried to reconnect via Ardunio and also via Smatto Firmware Upgrader. No success. The error is displayed here as an image.
What can I do?
If the image is not displayed, here is the error code:
avrdude.exe: stk500v2_ReceiveMessage():timeout

[William]

Hi, You may need to install the driver manually,
You can refer to this: https://www.geeetech.com/forum/viewtopi ... RlcFtWdCG4

When using the firmware toolkit to upload the firmware, the slicing software needs to be closed to avoid occupying the port.

Or replace the usb cable to connect.

[JuMe]

Hi, William, thanks for your message. The installation of the COM was successful, the Com is active. I have connected another device to the printer cable for testing that it works. So the signal is getting to the board. After that, there is something blocking the data stream.
No other programs are open, no slicers either!

[William]

Hi,Can you use the firmware toolkit upload tool normally?
For specific operations, you can refer to this:
viewtopic.php?f=20&t=69684

If the upload fails, you can provide your error message or
Video so that we can better solve the problem.