Upgrade K1 Max from CFS-C to CFS

Flagship K Series Creality Flagship K1 Max
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1

Hallo,

i had an K1-Max with old CFS System width many Problems with cutter and many trash in the printing room.

So i bought the new CFS-C, uninstall all modifikations from cfs system (cutter, extruder, …) and install all thinks from the new CFS-C Kit.
My problem is the firmware, my Printer has the actual FW (2.3.5.34) so ist makes no upgrade with the USB stick.

I want to downgrad to 1.3.xx version, but this seems to be impossible.

How can i fix it, that the printer accept the new FW/Setting for the CFS-C part?

Thanks a lot

Sven