Media box with USB OTG and external power supply connected to computer

[zygd]

Hello. Is it safe to connect Media Box with computer by USB OTG port (device is powered by it as well) and simultaneously connect external power supply to this media box?
Won't it make a reverse feedback on power line which can be dangerous for my computer?
I have never had an android device which had both USB OTG port and external power supply port.

[bluesmanuk]

What purpose are you thinking of in terms of connecting it to your computer whilst it already has AC powering it?

Normally the USB OTG is used for external devices such as flash drives etc

Some boxes are flashed via the OTG port with a cable connected to the computer whilst power is often supplied by the external AC, so I can't think of a reason why it should present any hazards for such a low power device.

[zygd]

I didn't make my question clear, i understand. And I see I made other mistake in question.
Well, didn't know earlier that cable designed for OTG functions has 4 and 5 pin soldered, and normal cable has 4 pin not connected. This way the device can recognized if OTG should be enabled or not.
The device has USB OTG port, but I want to connect it to computer with normal, not OTG cable.
I need it to update firmware with Usb Burning Tool. I was afraid that it will put power out on USB when I connect power adapter to the mediabox, and mediabox to computer, but now I think that if cable is not OTG this port will be working as normal slave port, not USB host port so no power out should appear there.

EDIT: firmware updated, confirmed on my Xperia M phone that when normal cable (not OTG) is connected, usb port is not supplying any external device.
Next issues has arised but I will ask for help in different thread. Generally, the device works and not works .