Sony KDL-46HX850 Can't upgrade/update firmware

[dkneyle]

Diagnosed this TV as having a failed main board which I've replaced with one from a KDL 55HX850. They are (supposedly) the same board.

Being 'Smart TV' it requires a firmware reboot when you swap out boards such as T-Con or main board. It starts with a black screen and flashing yellow and green LEDS, indicating it needs that firmware boot. The procedure described all over the web is to put the software into the root directory of a FAT32 formatted USB drive and it should load that up once plugged into USB1 port. But not for me. I can see the LED on the USB chip flash for about 5 seconds, but it goes no further. Are there any clever suggestions for what I need to do?

I downloaded the software, which supposedly is the most recent version from here: https://drivers.softpedia.com/get/TV...re-2-120.shtml

Of course, Sony is no help. "We no longer support that model. It is an old TV." It is only 12 years old, in wonderful condition, and it now has operational hardware - the only thing missing is Sony's firmware inside it! Sony simply refuses to enter into any sort of discussion about the TV. SHAME SHAME SHAME

[Diah]

what you did correct... but USB should no more than 4GB formatted FAT32 MBR Mode --- only leave the TV in this state over 40 minutes while yellow green flashing.. later you screen will light up

[dkneyle]

what you did correct... but USB should no more than 4GB formatted FAT32 MBR Mode --- only leave the TV in this state over 40 minutes while yellow green flashing.. later you screen will light up

Why do you say MBR Mode? I've formatted as FAT32 and FAT16; still can't get the firmware to load.

[dkneyle]

Firmware refuses to load up. I communicated with the guy that sold me the mainboard. Bear in mind, the TV is 46 inch, the board came from a 55 inch TV. But they are use same mainboard. Seller says the TCON has a firmware in it as well, which knows the mainboard is not correct for size of TV, hence why it wants the firmware upgraded. Given the mainboard had failed, I'm wondering if the T-Con was also damaged and might be preventing the firmware upgrade?

I've not had any experience with this nonsense of Smart TVs and the need for firmware upgrades. Anyone want to offer their thoughts on what might be going on here?

By the way, I've followed all the procedures for firmware upgrade. The USB memory chip flashes for a few seconds, so it seems it is being read. But it goes no further.