To do this I think you should use a microflow.
- On the entity create a second attribute to contain the integer
- Create a new microflow to convert your existing data
- Retrieve all objects of the entity you need to change
- Loop over the objects and set a change action in the loop to set the new attribute, where: if boolean = true then 1 else 0.
- Commit the list of objects
- In you existing logic check for places where the boolean is set and make sure the new integer attribute is set as well.
Hope this helps!