I have one of these I bought from Amazon in mid May and I can change the voltage on. I have two more that I received in August that I can neither flash the BIOS or change the voltage on. They have different BIOS P/Ns. The one that I can flash and modify the voltage on has BIOS P/N of 113-2E174CY-S41. The two that I cannot have the BIOS P/N of 113-E17430CY-S4l.

Just an FYI.