No Connection between MMU 2.0 and Eindsy  

RE: No Connection between MMU 2.0 and Eindsy

Hi,

I have the same problem.

- PC running on win10
- successful firmware update I3 MK3S+ (prusa3d_fw_MK3S_3_9_3_3556.hex)
- failed firmware update MMU2S (prusa3d_fw_MMU2board_1_0_6.hex)

I have a new MMU2S and after assembly I wanted to update the firmware. 
The firmware update of the I3 MK3S + went as it should. No problems here.

note: the manual described prusa slicer sending the correct firmware to the correct board so I connected both cables at the same time. 
Later I discovered in the firmware upgrade guid that it is recommended not to connect both usb cables at the same time.
(prusa contradicts itself). Perhaps this is the source of the problem.

The problem starts with the firmware update of the MMU2S. 
Prusaslicer cannot establish a connection and asks to press the reset button of the MMU2S. 
Nothing happens after pressing the reset button.

I noticed that none of the MMU2S leds had ever lit up so I started checking the cabling. 
I also checked the fuses in the I3 MK3S +. Everything was ok. 
Then I noticed that the red LED of the F.I.N.D.A. sensor does light up, indicating that power is indeed present on the MMU2S board.

Then I saw in win divice manager that the MMU2S is seen by windows under 'other devices' with the name 'ATm32U4DFU'. 
There is an exclamation mark: According to win10, no drivers are installed for this device. 
I removed all Prusa software and reinstalled it again without success. I tried this twice. 
I also downloaded the firmware again but the same problem persists.

I tried to reset the MMU2S to the factory settings, but this is also unsuccessful as no LED lights on the MMU2S board. 
So I cannot say whether the three buttons respond, but I suspect not.

Please help resolve this issue.