LG 42PM4700 Owner's Manual page 163

Caution when using USB storage device
❐
✎ If USB storage device has a built-in auto recognition program or uses its own
driver, it may not work.
✎ Some USB storage devices may not work or work improperly.
✎ Use only USB storage devices formatted with FAT32 or NTFS File System
provided by Windows.
✎ For external USB HDD, it is recommended to use device of less than 5V rated
voltage and 500 mA rated current.
✎ It is recommended to use a USB hub or hard disk drive with power supplied.
(If the power supplied is not enough, the USB storage device may not be
detected properly.)