@Kevin_Z hi kevin thanks for your help. FW 1.5.2 is available and i update it immediately, no more issue with new 1.5.2. Good job TP LINK.

@Kevin_Z Hi, i have same issue, after upgraded to the newest 1.5.1 firmware it cant play recorded video. I try your method to downgrade it with middle firmware first, but it says upgrade failed. Did...