Solve "Signature Verification Failed" error

I met Signature Verification Failed error  in CWM. when I updated my Galaxy Nexus(yakju) ( OTA  , JRO03C to JZO54K )

I remembered My Galaxy Nexus was rooted by Nexus Root Toolkit(NRT) 1.5.2.
I tried to root Galaxy Nexus again with Nexus Root Toolkit 1.5.5 ( newest version ).
And flash OTA again.
Now, CWM didn't say any error.

I use NRT again to root the device this time!