Hi,
To switch on your embedded Matrix Cam in a Manhattan 6900, do this WITHOUT any external cams fitted:
Press the Menu button
Go to the option labeled "6. System Information"
Enter 1212 (the receiver will carry out a reset)
Switch receiver off, and then on
When it restarts, press the Menu button, scroll allong to "CA Setup", and you should see your MR cam (probably V1.060 or earlier)
Note that older versions of the 6900 had a Magic Module embedded, NOT a Matrix Cam.
Now, if you want to update your embedded MR cam to a newer flash, the procedure is THE EXACT SAME as it is for an external MR cam. I have flashed my embedde MR cam (and several friends) many times. My only advice would be to use Funcard5 files, as I could never get it to work with Funcard6 files. Also, don't be tempted to use Matrix ReVolution files for your MR cam. If you do (and you will be able to update the cam with these files), you will not be able to update the cam EVER again! This is because, although the MR and MRV cams are similar, using MRV files on a MR cam disables the card update feature. If you have an external cam, you can go back to MR files by using a CAS2 programmer. However, since the MR cam in the Manhattan 6900 is embedded, you cannot remove it and put it into a CAS2 !
Hope this helps,
GAH