hi,
i've being using this Cello tv, uk brand, C40rts, HK.T.RT2841P638 main board, for a year or more.
Last week i've found an update, 3rd party, that i though it was close to my board. Inserted on a usb stick the install.img, started the Firmware update, ended, rebooted and nothing. The led (red-green) keeps flashing, backlight is on but to response on remote.
I've retried with original fw, no success. Hooked the uart Cp2102, putty, tried to swuu command (to update from usb), it goes for a while the get "cpu reset" on laptop screen that brakes the process and halt....