Q: setting up Flirc with Jetstream box and Univeraal remote MX-780

Hi all,

I'd like to replace a Roku that i am using currently with an Android Box, and the Ematic Jetstream box ticks all the boxes, except it's got a BT remote (as I understand).

My very simple 'system' consists of a TV, a pre-amp and powered speakers, so I need my remote to turn ON/OFF TWO sound devices, and all the media boxes designed to turn On/Off TVs and sound devices (be it a sound bar or a receiver) are set up for turning ON/Off only one sound device.

The Roku can be operated by an IR remote, but most android boxes cannot.

So, I need to "teach" Flirc to operate  Ematic Jetstream box from my IR remote, which currently is programmed for a Roku box (plus for TV, speakers and pre-amp).

I understand that after installing the SW on my computer, I would insert the Flirc USB into a port on a computer and use my MX-780 (currently programmed for the Roku) to teach Flirc commands I need.

What I don't understand is how Flirc would "know" that it would be connected to Jetsream box, not to, for example, a Xiaomi Mi Box ?

Or, is it a universal set of commands that would go through a USB on a device, regardless of its make?

Thanks