Flashing this board is generally done via a USB stick. The .rar file must be extracted to reveal a .bin file (often named MS3663T_S.bin or similar). Use a USB 2.0 drive formatted to FAT32 .
The standby LED should start blinking rapidly, indicating the update is in progress. until it stops.
This specifies the display resolution (HD Ready). Using a firmware with the wrong resolution (e.g., 1920x1080) for a 1366x768 screen will typically result in a "No Signal," distorted image, or a black screen.