Brick my Arduino YUN

The L13 and the RX LED are always ON. No upload is possible.
I think the bootloder is bad.

I try to programm the bootloader with arduino IDE 1.60:

avrdude: Yikes! Invalid device signature.
Double check connections and try again, or use -F to override
this check.

Fehler beim Brennen des Bootloaders.

And i try this Project:

but it dosn't support the YUN

What can i do to fix it?