MODIFY bfa_loop()

Hi,
I have a question.
If I should change the bfa_loop( ) function to show the post at the start page, with this structure:

Last Post for category one
______________________
Last Post for category two
______________________
Last Post for category three
______________________
Last Post for category four

Basically , I want to show the last article for all single category in my blog.
I saw that the bfa_loop function( ), show all article regardless of category.
Can I change the bfa_loop( ) fuction without the change is lost in case update theme?