Press and on the physical TV set (not the remote) while plugging the TV back into the wall.
Disclaimer: This firmware string is specific to Ruijie enterprise equipment. Modifying enterprise devices may void support contracts. Proceed with caution. tpd.rt2841.pb775 firmware
If the TV still boots, the simplest method is via the system menu. Device Preferences System Update Network Update USB Recovery (Force Update): Press and on the physical TV set (not