Network instability, file too large, or browser timeout. Solution: Use a direct Ethernet cable, clear your browser cache, or switch to a different browser (Firefox or Chrome, avoid older IE versions). Alternatively, use the TFTP method.
Locate the small reset button (often a tiny hole) on the LDW931. Use a paperclip to hold it for 10 seconds while the device is powered on. Ldw931 Firmware Update