Not sure about the B9 but worked on my C9.
Ok so this is what you need to do to update.
Find an lg service remote, or a phone with an IR blaster (some mobile phones have one) and using the in menu button enter the service menu(pin 0413). (you just need a TV controlling app if using phone)
You can find tutorials online if you struggle to enter the menu.
After you enter the menu go to system 2, NSU mode and change to Engineering Mode.
Do not touch anything else in engineering mode as you risk bricking your set.
Restart the TV and go to the normal update menu.
Turn off auto-update and then press check for updates and it will show up, maybe need to do twice?.
I am based in UK, cannot vouch for other regions.
After update reboot TV and computer. It should work.
After that go back into the menu and change it back from engineering to user.
How to get to the menu
https://www.youtube.com/watch?v=kHeu-PDCTSQ