The firmware you are looking for, with 800x600 resolution , is typically distributed as a .rar file for USB flashing on universal LCD/LED TV controller boards. Firmware Availability and Links

Direct downloads for this specific version are often found on technical forums and specialized software repositories:

: Once the blinking stops, remove the USB and restart the device.

Using the wrong firmware resolution can cause a distorted display or "no display" state. If the picture is distorted after flashing, you may need to enter the Service Menu (usually Menu + 1147 ) to adjust the panel settings.