[TIP] Uninstalling CWM on Xperia U (May work on other devices)
On your Xperia U you have to delete those files with a root file explorer:
This is not the most awesome tip on xda, but it may be useful for newbies =)
Want to know how I found that out?
Phone: Sony Xperia U
ROM: Stock 2.3.7
Bootloader: Locked (Not-unlockable)