In Cobalt 11, a new splash screen caching system is implemented where the splash screen is provided by the target web page via . See https://cobalt.googlesource.com/cobalt/+/rc_11/src/cobalt/doc/splash_screen.md for more information.
Long story short, you need to properly implement a local cache directory to store the to-be-downloaded splash screen so that it is available the next time Cobalt starts up.
You should make sure that SbSystemGetPath() (https://cobalt.googlesource.com/cobalt/+/rc_11/src/starboard/system.h#333) is implemented to return a valid directory for when kSbSystemPathCacheDirectory is passed in as the |path_id|. In particular, Cobalt should be able to create sub-directories within the returned path and write files to it that will persist when Cobalt is restarted.
The reason why this functionality has been modified from previous versions is so that Cobalt can support multiple apps (that may each want to show their own splash screens).