Looks like I was wrong to assume enigma2 has some internal limits for frequency. Changes to enigma2 may not be required after all.
Assumed that partly because in blindscan it says "Frequency values must be between 10700 and 12749" and you can't input anything outside this range.
In driver I only changed frequency range, diff is attached. Also includes change for upper band. Maybe hoping Nilesat301 extended ku would work, I doubt it will, but you never know.