Is there a way to launch the firmware on the console?

The emulator_banglejs2.js file is an Espruino binary designed to run in the browser, so you can't really run the Espruino binary from an Espruino binary :)

In theory you could build a native Espruino build with some Bangle.js functionality, but the best bet is probably to run emulator_banglejs2.js from Node.js.

There's an example of doing that here:

https://github.com/espruino/BangleApps/blob/master/bin/thumbnailer.js

But there is no REPL implemented - one could possibly be added though, in the same way it's done when emulator_banglejs2.js runs from the Web IDE.