If your soundbar is behaving unexpectedly—such as random shutdowns, volume inconsistencies, or failure to recognize inputs—a firmware update can address these issues.
The NB4540 is picky about USB drives. Follow these rules strictly:
Use a drive formatted to FAT16 or FAT32. NTFS formats are generally not recognized by the soundbar. lg soundbar nb4540 software update
The app will display your current version and check if a newer one is available. If an update appears, click the Update button to begin the process. Method 2: Manual Update via USB
: Insert the USB drive into the soundbar's USB port. Switch the input mode to USB. The soundbar will detect the firmware file and prompt the update process on its small front LED display. Do not turn off your unit while this is running. ⚠️ Troubleshooting Failed Updates If your soundbar is behaving unexpectedly—such as random
If you don’t have a USB drive, the app (available on Google Play and Apple App Store) can push updates via Bluetooth. However, this method is slower and prone to interruptions.
Ensure you downloaded the exact software intended for the NB4540. Files meant for the NB3540 or NB5540 will be rejected by the system. Post-Update Best Practices: Factory Reset NTFS formats are generally not recognized by the soundbar
Insert the prepared USB flash drive into the USB port on the back of the soundbar.
After updating, perform a factory reset: With the sound bar on, hold the Volume Down button on the unit until "RESET" appears on the display. This clears old cache and ensures the new firmware operates cleanly.
Write this number down. Compare it with the latest release on LG’s support site (see next section).