I removed my cams and defaulted all settings on my NVR5216-16P-4KS2 and upgraded successfully from DH_NVR5XXX-4K_Eng_V3.215.0000000.1.R.20170901 to latest DH_NVR5XXX-4KS2_Eng_V3.215.0000000.3.R.20171211 firmware.
Just thinking, Is it enough to default all settings? what does it mean for...