Look behind the unit and see the model number of your Linkstation.
Goto www.buffalotech.com and goto download, select the appropriate model and download the firmware.
Connect the Linkstation directly to your PC thru the LAN/Network cable.
Boot up your PC & Linkstation.
Extract the downloaded firmware and run the LSUpdater.exe file.
One it starts running, it will start to detect the linkstation.
If it detects the Linkstation, check the IP address listed there and assign a static IP in the same range to your PC.
It will not flash the firmware if the IP addresses of the linkstation and the PC is different.
Then proceed to update the firmware.
Another word of advice, when you power up the Linkstation, make sure the fan spins abit or check if there is a slight movement.
It might not be the firmware but could be the fan, as I've encountered before.