adb devices show phone in debug mod but not in fastboot mod When debugging mode adb devices , it will show my HTC magic. 

But when the phone is in fastboot mod , I can't see my HTC magic in adb devices.

I am using ubuntu 10.10 , 
my /lib/udev/rules.d/11-android.rules 

SUBSYSTEMS=="usb", ATTRS{idVendor}=="0bb4", ATTRS{idProduct}=="0c01", MODE="0666", OWNER="&lt;your user name&gt;" #Normal HTC magic
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0bb4", ATTRS{idProduct}=="0c02", MODE="0666", OWNER="&lt;your user name&gt;" #Debug &amp; Recovery HTC MAGIC
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0bb4", ATTRS{idProduct}=="0fff", MODE="0666", OWNER="&lt;your user name&gt;" #Fastboot magic
Have you checked that the idProduct value is correct? run lsusb when the device is connected in fastboot mode to see the vendor id and product id and check if it matches.

Also, I think it's not supposed to show up on adb devices when in fastboot mode, try fastboot devices instead.