How do you star wars battlefront 2 maps on star wars battlefront 1?

I know this is possible because I have the death star map from bf2 on bf1 and I've found other maps too as well.|||The only reason it's seen is because some maps from swfb1 were also placed in swbf2. I don't remember which maps specifically were duplicated but there are several. But this means that you cannot place swbf2 maps onto swbf1.