I'm no expert on upgrading, but I did notice that the upgrading documentation is only going till version 4.0.1. And the upgrade instructions are very specific, maybe you've missed a step.
For example, in update/common/scripts/ and update/database I see 4.0.1.>4.0.2. specific scripts.
Maybe someone from the eZ Crew can shad some light on upgrading 4.0.1. to 4.0.2.
Board member, eZ Publish Community Project Board - Member of the share.ez.no team - Key values: Openness and Innovation.