I've been following steps from http://dev.px4.io/simulation-gazebo.html , and got stuck pretty quicky on installing gazebo7:

System:Drones jakubczaplicki$ ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
System:Drones jakubczaplicki$ brew tap osrf/simulation
System:Drones jakubczaplicki$ brew install gazebo7

==> Installing gazebo7 from osrf/simulation

==> Downloading https://bitbucket.org/osrf/gazebo/get/1969aea.tar.bz2

######################################################################## 100.0%

Error: SHA256 mismatch

Expected: d02cfa845781e0d1b0af8a013c6a47a42dd3002986574d5b0cebbbfbe94ce0e3

Actual: fc74d669372a5a24b5ba8a812ae7933dca8be1b1880c8e8e4d0431c6d08a1046

Archive: /Library/Caches/Homebrew/gazebo7-7.0.0-20150824-1969aea.tar.bz2

To retry an incomplete download, remove the file above.

Have I missed something ?

Cross-post: https://groups.google.com/forum/#!topic/px4users/6wctgyMzfIY