That is, update C4 and it will work!!!

To update SD connect C4 interface, make sure you have 6xAA 1700 mAH rechargeable batteries inside which are already fully charged.

If no batteries or weak batteries, often parts of the update will fail.

If you put in non rechargeable, then there is risk of explosion!

Caution: 6xAA rechargeable batteries!!!!!!!!!

Good tips:

– How to install SD connect C4 battery:

http://blog.mbstartool.com/2015/08/25/step-by-step-instruction-for-how-to-install-mb-sd-c4-batteries/

– How update SDconnect c4 firmware:

http://blog.mbstartool.com/2015/08/25/how-to-update-mb-sd-c4-diagnostic-multiplexer/

– How to update SDconnect C4 to firmware v2.30:

http://blog.mbstartool.com/2015/08/25/instruction-for-update-and-install-v2-30-mb-sd-connect-c4-mux/

Thanks for laco210 for making important point.

Credits to
http://www.mbstartool.com/service/sdconnect-c4-xentry-on-mercedes-205-files-missing-16240.html