The screen flickered. The "SMART" logo appeared, but this time, a loading bar crawled across the bottom. A moment later, the colorful interface of the home screen burst into view, bathing the dark room in blue light. HK.T.RT2851V09
Since hk.t.rt2851v09 is obsolete, newer firmware is rare. Better to: hk.t.rt2851v09 firmware
If the TV still boots at all, try to back up the current firmware to a USB drive via the service menu. The screen flickered