Hello,
after several tests, mostly according to the motto trial and error, I tried to clone a Skreem module or its processor.

Here are all my test objects or victims:





First of all I noticed that although the Skreem modules from Crossfire and the immobilizer from Mercedes have the same part number 170 820 17 26 and the same processor from Motorola MC68HC05 1D69J but they are not the same.
The processor has three (or even four) areas where data is stored. One is an EEPROM which can be read and written again. Then a ROM and ROMB1 which can only be read and be written during production or by Mercedes.
And the ROM and ROMB1 of SLK and Crossfire are different, so that you can copy the EEPROM data from the Crossfire to the SLK processor, but it can't be the same.

For copying I used an Orange5 programmer.

How do I distinguish the Skreem from Crossfire and SLK?

As you can see, the modules are 100% identical from the top:





The only difference between the modules is that the Crossfire Skreem has a sticker on the back: