There is no JTAG frequency showed in the hardware setup. Is it because we use the on-board blaster?
But we try to lower the frequency to 6MHz, it works. And rbf can be downloaded now.
The USB-Blaster™ II download cable has a default clock frequency for TCK (JTAG) of 24MHz. The frequency may be changed to lower frequencies where signal integrity and timing does not allow operation at 24MHz