After a day of tinkering with the car (replaced the speakers with working ones), my damn airbag light is flashing...
I tried the reset but alas, it's still there.
According to this guide: Guide
There's an issue with my Driver Air Bag Module. But I have no clue where it is or how changing the speakers somehow caused issues with this.
I did replace the tweeters at the front which was a bit of a dodgy job but it all looked fine so I don't know if I somehow messed something up?