Hi Erik,
the update TC70 BSP introduce few changes in the filesystem permission to comply with Google's Android Compatibility Definition Document for Android KitKat that was necessary to comply with Google requirements to be able to release devices with Google Mobile Services.
One of these changes is that Non-system applications cannot use /data/tmp for storage. Your best option would be to switch to use the "ExternalStorageDirectory" (in TC70 case it's the internal 1GByte partition available)

Instead of saving under /data/tmp/, use Environment.getExternalStorageDirectory(). You need a read/write permission to do that. You have to add these two lines into the Manifest of the application ! (I tried to add those lines into the /androidTest/Manifest.xml file, but it has no effects).

While it solves the problem of finding a common directory to save/read temporary data.

~Pietro