The firmware installed successfully, but the panel mapping settings are wrong. You need to enter the Service Menu (Menu + 1147 or Menu + 2580) to adjust the "Panel Config" or "Mirror Mode" settings.
Downloading the TP.SK518D.PB802 software for free is a straightforward process. Here are the steps: tp.sk518d.pb802 software free download
A complete guide posted on XDA Developers walks through the process of obtaining full Magisk-based root access on this hardware platform. The process involves patching the boot image using Magisk and then flashing that patched image directly to the boot partition using the dd command. Because the board has Verified Boot (AVB) disabled or set to “orange” status, this is possible without triggering security lockdowns that would prevent the modified image from loading. The firmware installed successfully, but the panel mapping
The factory menu on many TP.SK518D.PB802 units contains an option to enable Android Debug Bridge (ADB) access. Once ADB is enabled, users can connect to the television via a computer on the same network and issue root-level commands. Here are the steps: A complete guide posted
If your television boots at all but exhibits only minor problems, consider backing up the existing firmware before making changes. Technicians use hardware programmers such as the RT809H or EMMC adapter tools to extract full dumps of working firmware from the board’s eMMC chip. This backup serves as a safety net if a new flash fails. However, this requires specialized equipment and is not typically accessible to regular consumers.