iOS 4.1

If a Folder icon background (& Folder icon) doesn't change go to :

"var/mobile/Library/Caches/"  and delete "com.apple.Springboard.folderSwitcherLinen" file. 


iOS 4.2.1 and newer.

If a Folder icon background (& Folder icon) doesn't change go to :

"var/mobile/Library/Caches/"  ,there are 4 files,delete :

com.apple.SpringBoard.folderSwitcherLinen.0
com.apple.SpringBoard.folderSwitcherLinen.1
com.apple.SpringBoard.folderSwitcherLinen.2
com.apple.SpringBoard.folderSwitcherLinen.3

JackieTran