Interchangeable U2 chip beteween iPhone 4/s and iPhone 5/s?

I have a 5s with water damage that I would like to repair but don't want to replace the U2 chip without some practice. I have an old iphone 4 and 4s's with water damage. Since the 4/s's are going away and are not supported, I don't really care if I mess them up and was going to practice removal/installation of the iphone U2 IC BGA chip. I can't find any sellers that are selling 4/s U2 chips. Are the U2 chips for 5/s the same as the chips for the 4/s chips? There are several sellers on ebay and aliexpress that sell the 5/s U2 chips, but I haven't found one that says that they are compatible with the 4s.