My friend and I, who both have Sprint Heros and different brand 3.5mm headphones, noticed this same issue:
If you turn on the Sprint Hero with headphones already plugged into the 3.5mm headphone jack, the phone doesn't detect any headphones when the device starts up. Then even if you unplug and re-plug the headphones back into the 3.5mm jack, the phone will never detect any headphones.
The only workaround seems to be restarting the phone without any headphones plugged into the jack, and once the phone starts up, then plugging in the headphones.
Has anyone else noticed this?
BTW, my phone has PRI 1.70_003 with EvDo rev. A showing properly
My friend's phone (which exhibits the same headphone bug) has PRI 1.68_003 showing EvDo rev. 0
So it looks like a bug with both "hardware versions" out there.
That's already been identified in the main bug tracker thread here: http://community.sprint.com/baw/thread/23135?tstart=0
Edit: At least for the most part... there are other threads too that discuss that exact issue.
Message was edited by: kenyu73