This is the most comprehensive archive. Search for "TX9 Pro" to find various versions, including the stock Android 7.1 Marshmallow or newer 9.0 builds.
Never unplug the power during the flash process, as this will permanently damage the hardware.
Since there is no single "official" manufacturer website for these generic Android boxes, the community relies on trusted firmware repositories. Here are the most reliable sources for the TX9 Pro: tx9 pro android tv box firmware link
Once you have located a link and downloaded the .img file, you generally have two ways to flash it:
Most standard TX9 Pro units are powered by the Octa-core CPU. However, some newer "Pro" versions or clones may use different chipsets like the Allwinner H616 or different WiFi modules (LP6330 vs. RTL8723BS). This is the most comprehensive archive
Match the build number of the firmware link to the one currently on your device whenever possible.
Flashing new firmware will wipe everything on the device. Since there is no single "official" manufacturer website
This is the preferred method for "unbricking" a box. You will need a USB Male-to-Male cable to connect the box to your PC.
Often hosts direct links to updated SD card and USB burning tool images. Community Forums: