I owned a iPAQ 612c. If you have any question or would like to share with me. I m willing to test on behalf of you.
Basically i had using this unit for a few weeks. So far i don't found any big issue unless i have found out that when this unit overheat (u feel the warm), u'll experience it unable to charge the battery via sync or power adapter.
2. I was doubt that i saw previous post someone said that this unit can support up to 8GB SDHC microSD card, but as far as i know from HP document it states only 2GB. And do not support SDHC in this devices.
3. My GPS just work well by using Garmin and mal-sing maps. But the cons is that some of the time, it will have difficulties to start the GPSProxy, it shown all 0 degree, 0 values so GPS is not able to use unless more satelite is being detected.
4. Alarm a little sucks. The default alarm ringtone unable to change to MP3 or so. It was unable to wake me up all the time ... lol
5. I saw from previous thread, someone mention how to use the keyguard function. By right, u need to
Start -> Setting -> buttons -> lock tab -> check the "Enable keyguard" box and OK.
When your iPAQ enter standby mode, it should be automatically lock the keypad, so when u trying push the power button, it will prompt to unlock the keypad by press and release the left and right soft key.
6. the left "OK" button is just to disable the smartwheel function, i guess someone have provided the wrong info in prev post.