glFramebufferTextureFace/Layer/2D

To create 2D FBO using single cubemap face, we could use glFramebufferTextureFace: http://www.opengl.org/sdk/docs/man4/xhtml/glFramebufferTextureFace.xml

However this is not implemented on NVidia drivers (259.39).
I was albo unable to use glFramebufferTextureLayer for this purpose (got GL_INVALID_OPERATION error generated. <texture> does not name a layered texture.). I was however successful with simple glFramebufferTexture2D using GL_TEXTURE_CUBE_MAP_POSITIVE_X + face.

Is this driver bug or spec bug?

See also http://www.opengl.org/discussion_boards/ubbthreads.php?ubb=showflat&Number=280943#Post280943

To create 2D FBO using single cubemap face, we could use glFramebufferTextureFace:

That function doesn’t exist. That’s an error in the documentation; the GL spec does not define any such function.

This wiki page does a better job of explaining your options.

Thank you for clarification.