How do I stop the auto resize of fs on first boot

I am trying a have a pi with 2 partitions due to needed to store data that windows can read.

I know with the 18.04 images the resize2fs is run automatically on first boot. I found however that after this happened it was very to size it back down. So I would prefer to just size up and create the other partition on my own.

Any help on how I can turn off auto resizing would be great. I think I saw in another thread that it may be a python powered script, but not sure where to find it