I have installed on my mid 2009 Macbook Pro (Macbook 5.4) Dosdude1 Catalina Patcher. It is working great. I had a Bootcamp partition on the SSD with Windows10 installed previously with El Capitan MacOS. The Bootcamp is also working fine. My question is whether the links between Catalina MacOS and the Bootcamp continue or those two partitions are completely independent.