Do you have a Dutch oven?
Do you have a remote internal meat thermometer?
If so, remove butt from smoker and place into the Dutch oven.
Any container that you can seal tightly will work--like a roasting pan with tight lid.
Place aluminum foil around the entire container and then place the lid on it.
The foil will keep the hole where the remote read thermometer lead from leaking moisture.
Set the pan in the oven, in your house's oven, and set temp to 220/225.
Leave the butt there until your internal temp probe reads 195 F.
At that point, remove butt and let is sit for at least 10-20 minutes.
If you do not wait until the temp is 195, the tough parts do not liquidfy. Once that temp is achieved, you are good to go for taking a fork and shredding the meat.
Point of discussion here: A Boston butt will have absorbed enough smoke flavor at the 2-hour level in any
Masterbuilt smoker. More smoke is NOT better. I have found the best solution is to move butt roast to my kitchen oven, place it in my Dutch oven. seal the top with aluminum foil and watch the remote internal temp probe like a hawk. Once it reads 190-195, KILL the heat--remove from oven, let the butt rest at least 30 minutes. Pulled pork that way is totally mouth-wateringly impossible to resist!
Prof Bill