Babaganushh

I tried searching for this situation but haven't had any luck so far. I purchased an 80g hard drive to upgrade the old 30g that was in my z2. The 80g is being updated with all the latest software, maps, etc. Both drives are also being unlocked so I may transfer music. However my question is how do I tranfser music from the 30g to the new 80g so I don't loose anything?