J-link RTT viewer freeze when download from keil

[sosse]

I connect to nrf51 DK board and PC using USB. I used RTT Viewer to see RTT log output. But when I try to compile and download from keil to the board, I got several WARNING and the RTT viewer is freezing. (see as follows..)

I do not have any other problem using other DK board, but only this board cannot download correctly while I turn on RTT Viewer (FYI, I works fine without the viewer). Someone can explain how can I fix this?? Thank you.

edit: I think it happens after I update J-link f/w to 5.10 version by using nRF Go Studio.

[sosse]

I answer myself... I figured it out. I don't know what is wrong with the newest version for J-Link F/W. From this link, version 160212 seems not works properly. Thank you.

[sosse]

Still I don't know why the RTT viewer is freezing when I update J-Link F/W...Somebody have same issue?