Cloning is a process where you take data from 1 item and copy it to another to make an exact replica.
If your speedo has failed completely, has a hardware or PCB fault, you need to fit a new speedo.
You can but it might come with issues.
The odometer won't show the correct distance travelled. It will show the mileage/KMs of the
car that the speedo came from but as soon as you start the car, that reading will show ------.
That can cause problems during the annual car test of your country.
If the odometer reading of the speedo that you fitted is lower than the car you put it into, the
odometer reading wll quite often fix itself eventually and display the correct distance reading.
If the donor car has a higher odometer reading, the speedo will never show the correct distance reading.
The donor speedo also contains the incorrect VIN code for your car. This will flag up during diagnostics on MB Star.
If you went to smart, they'd want you buy a new speedo and then charge you 1 hour labour.
You are almost certainly looking in excess of £350. Fuck that.
Why not just buy a 2nd hand speedo from eBay and clone your existing speedo?
It's actually not all that hard to do. Depending on the method you use and
the tools you already have, it could cost you less than £10 for the tools.
You will have to buy a 2nd hand speedo. Take a look on eBay.