What is the max height? Does it climb to that height then drop down? How much does it drop diwn? Goes it actually RTH at like 100’ or so? Have you tried setting the RTH to 100’, or 50’ - and foes that work? I assume you calibrate before your first flight? RTH is set by GPS - goes it hover in place or wander? Give us more data. Try a few different heights and see if that works. I assume you are talking about the RTH height not the software - is that right?