11-02-2014 04:15 AM - edited 11-02-2014 04:20 AM
Depends on the model STB. Some its in the regular menu under settings/audio&video/video format.
Others like the 7xxx ARRIS (previously called Motorola) you can go into the hidden menu to change as well and IF YOU WISH also select native aspect.
With the DVR/STB on, TV hit power off on the DVR/stb, followed by ok and menu(you may have to use the remote for the ok and Menu as newer boxes don't have them on the boxes). Should bring up a User settings where you can select Native and must also select the resolutions your set supports. Note 1080p24 and 1080P30 are supported by the box this way but only if the program comes over in that format. Some VOD MAY be sent out in 1080P.