This is an upgrade failure. If you do not power off during the upgrade, it is not your problem. Because usually the upgrade process is to download the upgrade package to the memory of the set-top box through the cable TV network (like the computer, it is cleared after power failure), and then rewrite the set-top box version and the original program stored in flash according to the upgrade program of the set-top box itself, which requires the manufacturer's personnel to use their professional equipment.
Try the AV cable connection. If not, it is the box itself (the upgraded version of the system is incompatible with the TV). Try changing the box or plugging it into another TV.
Finally, call your local radio and television customer service directly to tell them about you.
