There are no official firmware updates to this sound bar, but looking at the comments on the LG page, someone managed to use the firmware for LG SK4D 2.1 Sound bar which is what I did and it worked!
All you have to do is download the zip file and unzip the binary file into a flash drive that is FAT32 formatted, turn on the sound bar and set input to USB, then plugin the USB drive, the front LED’s will flash left to right until the sound bar turns off, firmware is now updated!
Download the zip file below and remove the “.pdf” extension. That will contain the latest SK4D firmware as of 11/14/2022
Support Page to firmware
https://www.lg.com/us/support/product/lg-SK4D.DUSALLK