Software update Mercedes failed

Mercedes E-Class (C207)

This one underwent a software update of the engine management at the Mercedes dealer, after which the ecu turned out to be unresponsive. Despite frantic attempts by the mechanic concerned, no more life could be breathed into it. The only solution was to order a new ecu. Unfortunately this type was in backorder: delivery time unknown.
Now our help was called in. First we received the loose ecu. After inspecting the software, we found that the eeprom part got corrupted during the update process. Since we have a large collection of backup files, a similar eeprom dump was virginized.

Just to be sure, the corresponding flash memory was also programmed and yes: on the workbench, the ecu was approachable as usual and after checking, the immo was indeed virginized.
After returning the ecu to the dealer it was installed and reprogrammed with the xentry diagnostic system. Since the ecu was now virgin the xentry system sees the ecu as if it were a new one. Unfortunately, again after programming the ecu the same problem.

After brief discussion, it was decided to put the car on transport to Kerkrade.
First we flashed the ecu back to the way it left here.
Since we also have online access to Xentry with flash privileges, the first decision was to program the ecu as the dealer does, to see if it works here. But no, after flashing xentry whined that the ecu was in ' boot mode'. Now what?
Fortunately we have equipment that goes 'beyond dealer level'! After re-flashing the virgin software, we manually personalized and activated the DAS (Drive Authorization System), then used xentry online to perform only the SCN coding. After programming the injector codes and various adaptation values, the engine started again!
Apparently there is a bug in this software version on the Mercedes server, which always causes it to fail.