HTC has posted a tweet cautioning against upgrading the EVO 4G with a leaked Android 2.2 update:

“Please be aware any update.zip floating around for EVO are not final and may cause problems. Official updates are coming OTA next week!”

It appears that this may be similar to the Droid Eris MR3 leaks, which while signed and pushed to a handful of devices, were not final in bootloader and baseband changes. As such, while the payload may be the same (in terms of Android files), the update may still have adverse affects. HTC pushed this update in a test wave, to a few EVO 4G units, before removing the update from Google’s Android update servers.