as posted on the forum:
Just got my Uno after finding semi-permanent projects for two previous Duemilanoves. Upgraded to Arduino 0020. After rebooting, and power cycling the Uno, there’s still no serial port for the Uno.
The board is noted under Linux, which reports an unknown device with ID 2341:0001. On my MacBook (10.6.4), System Profiler lists:
Communication Device: Product ID: 0x0001 Vendor ID: 0x2341 Version: 0.00 Speed: Up to 12 Mb/sec Location ID: 0x24110000 Current Available (mA): 500 Current Required (mA): Unknown (Device has not been configured)
There are no /dev/tty* or /dev/cu* devices that correspond to the device.