Hello Victor,
On our i.MX6QDL SabreSD board, only USB OTG is supported. And the USB OTG is desgined to be dual role mode. so if you want to test it's Host mode, you should connect a USB OTG to HOST cable to MicroUSB connector, and connect USB device on the other side.
If you are using the Evaluation board, you don't need to modify android source code. the function has been supported.
[Note] For USB OTG , there 2 kinds of cable:
-----USB OTG cable : it makes USB OTG work at device mode, such as USB charging cable for mobile.
-----USB OTG to Host cable: when the cable is connected to microUSB connector, USB_OTG_ID can be pulled down to LOW, and USB OTG working at HOST mode.
Have a nice day!
TIC weidong sun