Thread:Talk:Download from Git/Update error

When I want to update all extensions, I get an error.

sh-4.1$ git submodule update --init fatal: reference is not a tree: 655d019b84689e37b3fb1018600f629c657fb575 Unable to checkout '655d019b84689e37b3fb1018600f629c657fb575' in submodule path 'Persona' sh-4.1$

Anyone can help me with this?