Native 1366x768 HD, though some variants support up to 1920x1080. Where to Download:
The standby light should start blinking rapidly, indicating the update is in progress.
Press and hold the button on the TV panel (not the remote).
The is a common universal three-in-one LED TV motherboard used in various 32-inch to 42-inch models, supporting a standard resolution of 1366x768 . Firmware Details & Source
Specialized repair sites like Dip Electronics LAB or Alibaba/AliExpress product pages sometimes provide software links to buyers for resolution matching. Installation Guide (Write-up)