Thanks!
If you have tried three different firmware files and nothing works, suspect hardware failure. The main board can be replaced for $15–$25 on eBay or AliExpress. Sometimes, spending $20 on a new board is more cost-effective than spending 4 hours debugging a corrupted NAND chip. t.ms638.733 firmware
If your TV still boots but is glitchy, use an (like CH341A) to read the existing firmware before flashing anything. This gives you a fallback. Thanks
If your display works fine, leave the firmware untouched. leave the firmware untouched.