If you find yourself among the thousands of HTC EVO 4G owners who happened to flash the unofficial Froyo update to your phone a little over a week ago, we’d like to let you know that an official OTA fix is now available. HTC is pushing out a patch for all phones running on 3.26.561.3 which will update the phone to the official 3.26.561.6 ROM build. To grab your update, simply press: menu > settings > system updates. Keep in mind that if the download is not yet available, you can always bump up your handsets date by a few weeks which should trigger the download process. Be sure to let us know how it goes.
Source: Sprint Community