Thanks for the knowledge

Excellent knowledge and explanation of how temporary it can be

7:52 you cannot call it a reflow. Because proper reflow is when all solderballs under the chip are melted - you recognize it when you can slide (move) the chip a little bit by touching it with the tweezers. Some solderballs under the chip have corrosion, holes, cracks, so there is no connection. What you did, is only a warm up the solderballs. Why it is working now? The metal expands when... is hot, and shrinks when is cold. So when you apply the heat - the solderballs expands and it temporary fix the cracks - you have a temporary connection. Laptop is working but, it is an illusion- after few hours, or on next day morning - the laptop will be cold and the cracks will comaback. BUT when you do a proper reflow - when the whole chip has 220-230deegrees Celsius, then all solderballs are melted and only then the chip can move and goes down, and when it goes down, then all balls can reform, reshape itself, so the cracks and holes will disappear. It cannot happen when the chip is not moving because the other solderballs (without cracks and holes) are solid and not allow the chip to goes down. All the solderballs have to be melted to do the trick, to fix cracks. And only proper reflow or reballing, gives you another 3-6-12 months of working laptop. Your method gives only few hours. Let's play the game - fix the gpu in your way, check if is working, then put the whole laptop to the fridge for one, two hours. Then check again. Did you lern it from the Sorin? Because he is fixing gpu in the same wrong way using a very small hotair nozzle and by heating only the frame / edges of the chip without the core.