DSO Nano V3 (no SD) Calibration

I just received my Nano V3 (the version without the SD card) and I went to check accuracy with a power supply and my calibrated Fluke 87v. At 3 VDC I noticed the Nano was reading 2.88 Vavg. Not the greatest but it would work for what I want to do, which is check audio levels.

I noticed the calibration menu and I wondered if I could adjust it to be more accurate. I fiddled around with it and I was able to get the reading pretty close, 3.04 Vavg. Great, now I just have to save it, and there is the problem, I cannot get the calibration to save. Every time I power cycle the unit the calibration resets to factory defaults.

Does anyone know how to get the calibration to save?

My DSO is way off in measuring voltage. Tried the OT menu option. Cannot even get it close. When I connect the probe to the signal generator I only get about 200mV. Any suggestions.