Combine the pork pieces, soy sauce, vinegar, garlic, bay leaves and black pepper in the inner pot of a 6-quart instant pot.
Press the “Sauté” function. After a few minutes, the screen will display “Hot”, indicating that the working temperature has been reached. Without stirring, bring the mixture to a boil. Continue boiling for 5 minutes.
Press “Cancel”, stir the mixture and then add the water. Place and lock the lid and then set the valve to the sealing position. Press “Pressure Cooker (High)” and manually set the timer to 10 minutes. The cooker will preheat for a few minutes and then the timer will start counting down.
When the time (10 minutes)is done, press “Cancel”. Carefully quick release the pressure by turning the steam release handle to the venting position (I use a long wooden spoon to do this process). Wait for the float valve to drop down, indicating that all the pressure has been released, before opening the lid.
Press “Sauté” and let the sauce boil for 10 minutes. After 10 minutes, correct the seasoning by adding more soy sauce if needed. Continue to simmer for another 5 minutes, depending on much sauce you desire.
Press “Cancel” and unplug the instant pot.
Transfer the adobo to a serving plate. Discard the bay leaves and serve with rice.