Even with the application that patches the /etc/permissions/platform.xml, I have found certain apps still do not work correctly. Dolphin Browser, for example, cannot switch to /storage/sdcard1. It keeps saying it can't find it and I need to ensure I don't have "USB Mode" enabled, which I don't even have as an option when connected to a PC.
I also have init.d installed on my machine and I had startup scripts that mounted various directories from my external to the internal SD card to "fool" the device so that apps that wouldn't save to the external but the internal would save across a mount. Well, that no longer works. For example, Amazon MP3 will not save downloaded music anywhere except to the internal sd card. I had my startup scripts mount an amazonmp3
directory on my external SD card to the internal amazonmp3
directory on the internal memory card. When I proceeded to download music, it didn't show up in the external directory. However, I noticed that the internal sd card's memory did decrease. I then unmounted the directory and saw that the Amazon MP3 app was ignoring the mount under KitKat and directory saved the files into the /storage/sdcard0/amazonmp3 directory, even though it was mounted to the directory on the external SD card. It did work under JB and ICS, but apparently, with KitKat, some apps will still write directly to the native directory on the internal SD card, ignoring the fact that I've mounted a different directory to it.
The stock Moto camera will
write to the external SD card if you go and change the setting for it. However, the Google Camera does not give you any option to store your pictures anywhere except on the internal SD card memory.
Remember, apps can write to the external card, if you don't apply the "patch", but only to what is considered a protected are (the /storage/sdcard1/Android directory structure) and then, they can only write to a directory that the app created. They can read other directories, but they cannot modify them.