Hi Wolfgang,
I believe you can download firmware from TC Electronic here:
https://www.tcelectronic.com/Categor...ogtrans(en|en)
Last year I downloaded their firmware app to update software of a MkII mainframe with original black icon. The app installed versions appropriate for the hardware:
TC Icon: 7.5.00
Frame: 6.50
DSP: 6.50
Ethernet SW: 8.10
I hope this helps.