Per instructions from LG.
1. USB needs to be formatted as FAT32
2. Create a folder named LG_MONITOR on your USB and paste the firmware eg: SM5J_UL3J_03.08.80.epk into the folder.
3. Plug the USB into the LG display
4. To launch the Software Update menu manually, follow the steps below.
Press the SETTINGS button on the remote controller, or click the
button on the Smart Home screen.
Click the General icon located in the left panel. The settings menu appears on the screen as shown on the right.
Press the button 7—for seven times—on the remote control. Then the Software Update menu gets launched as shown below.
Select the firmware file to update with.
In case you are downgrading your firmware, i.e. updating with a version lower than the installed, enable the Ext. MICOM URSA* option (marked in red above). Note: after a downgrade your player might report the wrong time, this is known by LG and you will simply need to re-adjust the time.
Click the UPDATE button to start updating with the selected firmware.