Finally, Samsung Galaxy S4 I9500 supports ExtSd2InternalSd. Yes, you can swap Galaxy S4 internal and external storage now. Personally, I don’t prefer this method because internal NAND memory speed is a lot faster than external SD card. See this article for more info – Galaxy S4 storage speed ~ internal NAND vs external SD card. Don’t swap the whole thing, just move Galaxy S4 games data to external SD card will do. This will not slow down the whole system but just slow during game loading, right?
Okay, still looking for ExtSd2InternalSd method? Please refer to this guide – How to swap Galaxy S4 internal storage with external SD card?