If you encounter the dreaded "NO USB" or "ERROR" message, don’t panic—reformat your drive and try a different USB port (the NB4540 has only one, but sometimes re-seating helps).
Remember: firmware updates fix bugs; they do not transform hardware. Your NB4540 will never support Dolby Atmos or eARC, but a successful update will make it stable enough to serve as a reliable TV speaker for years to come. Drop a comment below or visit the LG Community Forums. If you successfully updated your NB4540 using a rare firmware file, please share the version number to help other owners. lg soundbar nb4540 software update
Last updated: May 2026
Do not use this method if your soundbar frequently disconnects from Bluetooth. A failed app update can brick the device. If you encounter the dreaded "NO USB" or