Cannot access local storage on HTC Desire HD with Linux
Have you switched Mass Storage mode on? Not sure about Desire HD, but it should be either in USB Settings under Settings -&gt; About Phone -&gt; USB Settings, Settings -&gt; Wireless and network -&gt; USB Settings, or it may show up directly in the notification bar when USB is connected.

If this doesn't help, do a lsusb after connecting the phone and check it's detected.