Why the app keeping reset

[BRN]

Hi,

the bootloader addr is start form 0x28000, and I checked my application code, it only reached 0x25B00.

I called the fstroge to erased a page Flash start from 0x27000. then I writed 4 bytes into flash address 0x27000.

everything goes fine ecepte when I re-powerUp the demo board, four LEDs keep fast blinkng, it seems keeping reset, I pressed one of the buttons, the system will enter bootloader,

I can runing the DFU, but the system is still keeping reset, I assume because the last 2 page of the applicaton code area won't erased by the bootloader, DFU can;t fix the problem.

Please help.

[BRN]

I debuged, the reset rease is " fds_init() returned 0x0B" 0x0B shoud be FDS_ERR_NO_PAGES.

If I don't write the FLASH, the system runs well, when I werite data into FLASH, then reset, the system cannot work.