Heat the olive oil in a large pot over medium-high heat. Add the pork chunks and brown them on all sides, working in batches if needed. Remove the pork and set it aside.
Add the onion to the same pot and cook until it softens. Stir in the garlic and cook for one minute more. Sprinkle the flour over the onions and stir for another minute to cook out the raw taste.
Pour in the Guinness and scrape the bottom of the pot to release any browned bits. Add the beef broth, bay leaves, and thyme. Return the pork to the pot and bring the mixture to a simmer. Cover and cook for 45 minutes.
Add the potatoes and carrots. Season with salt and pepper. Continue simmering, partially covered, for 30 to 40 minutes until the pork is tender and the vegetables are cooked through. Remove the bay leaves before serving.