I have also tried write the whole reg to 0x0 and write CAN_WU_I bit to 0, the flag can not be cleared.
fs2400_write_register(&l_xDev, FS2400_REG_M_WU1_FLG, 0x0)
fs2400_write_bit(&l_xDev, FS2400_REG_M_WU1_FLG, FS2400_REG_M_WU1_FLG_CAN_WU_I, 0)
Any other registers should be re-init after a CAN wake-up pattern?