This method is majorly
out of date. Generally, every update breaks the current root method, and a new one must be found. By now, this is 3-4 cycles old. Please check XDA-Developers
forums or unrevoked
for alternate (and current) methods.
This one is sure to make plenty of people happy: it looks like there's finally a root method for the latest EVO OTA. The method was discovered by XDA-Devs user Dan Wager and is based on Sebastian Krahmer's Droid 2 root - although this seems to achieve root by downgrading to Android 2.1 and flashing unrevoked. Read More
This is exactly why I love Android so much and the awesome developer community around it. Case in point: the official Android 2.2 update for the EVO 4G has already been rooted by netarchy over at XDA-Devs. Yea – the update that was just released yesterday… pretty impressive stuff. Be forewarned, though – the update may not play nice with the previous (non-final) update that was released.
You might be able to just flash this over the leaked ota, but I advise doing a full wipe before flashing just to be safe.