Hello @xu ,
You cannot use 'EraseSector' system call to erase SFlash. You need to use 'WriteRow' system call to program SFlash.
There are some restrictions you need to be aware of while programming SFlash. The system calls which one uses for programming SFlash are different than that for code flash / work flash in Traveo II. User cannot program all the sections of SFlash. Only certain sections of the SFlash will be allowed to program by the user through WriteRow system call. Please refer to sub-section ' WriteRow' under chapter 'Nonvolatile Memory Programming' in Architecture TRM (Document No. 002-24401) for more details.