@sygyzy_twitter response: I took a look at the schematic, it looks like only the bluetooth module is not labelled. I'll try to dig up the name of the module, but forewarning: it's a Chinese module that isn't well documented.
Disabling the module completely isn't an option since it acts as the main audio interface - audio from the Omega is routed through this module as well.
However, because it's the main audio interface, you can still achieve the effect of disabling bluetooth by always setting the module's input source to USB (audio coming from the Omega) as opposed to bluetooth input. In this scenario, the Oboo will still accept bluetooth connections, but the bluetooth audio won't play on the speakers. Just like how a TV can have multiple inputs but play only one at a time.
Setting the input source is implemented in the audio manager: https://github.com/ObooSmartClock/Oboo-Packages/blob/master/oboo-clock-cards/src/audio-manager/audio.js#L57