I request modem change from ISP, the new one is also with 1.0.4 firmware. Same errors happened for a period of time, then I learned that I'm not restricted to the firmware level of Isp, so I upgraded...

Model : Hardware Version : Firmware Version : ISP : Using DSL-6740U for internet connectivity provided by Dsmart in Turkey. Firmware level is 1.0.4 ( cannot be upgraded by user, isp provided ) from...