Put in a cruise altitude of FL50. Or FL80. Or FL100. It doesn't display cruise mach.
- As long as FMC has a cruise level below FL 260 is will not predict a CRZ Mach;
Strange my B737NG will predict an CLB, CRZ and DES Mach below FL260.
And by the way I think I can even fly IAS at FL 410 in VNAV PATH. (Though not recommended)