Heat 2 tablespoons of oil in a large pan and saute' the carrots and the cabbage. Add two tablespoons of water and season with one tablespoon of soy sauce. Let the vegetable soften and transfer to a plate. Set it aside.
Using the same pan, add the remaining oil and brown the pork on both sides. Cover the pan, cook the meat until it changes its color, and let it release its liquid. When ready, push the meat to the side of the pan, and add oil if necessary to saute' the garlic and onions. Add three cups of water and cook the pork until tender. Check the water/broth in once in a while to remove scum.
When ready, season the meat with soy sauce and season with salt, ground pepper, onion, and garlic powder. Season according to your liking.
Add the Bihun noodles, let them soften, and let them absorb the remaining liquid.
Add the vegetables and mix gently.