Clearing NVRAM on Yosemite shows password entry
Solution 1:
You can also from the terminal in Yosemite run:
sudo nvram -c
and then restart the computer.
Solution 2:
This means that a Firmware Password has been set on that Mac. A simple way to disable this is to remove some RAM and restart. Shutdown, replace the RAM, and the Firmware Password will be disabled.
This is the Firmware Password prompt:
