Firmware Password - Keyboard Layout

Hello,

i have a Mac mini Late 2012 with german extended keyboard.

I set the firmware password with US keyboard layout.

When i now try to enter the fimware password at boot time the default keyboard layout is set to german.

My problem is that i use a '\' (backslash) as part of the password. Unfortunately the firmware password

input field doesn't support the option key which is needed on german layout to get the backslash

character.

How can i reset the password?

Best,