Output as follows:

Macintosh:~ Dragonfly$ calibre-debug -d
USB devices on system: [(1452, 32773, 512), (1452, 33346, 22), (1452, 566, 129), (1452, 32774, 512), (1452, 34055, 1049), (1507, 1544, 2305), (1423, 37395, 256), (1423, 4097, 1), (1452, 775, 832), (1317, 42149, 788), (1452, 32773, 512), (2652, 17664, 256), (1452, 33299, 384), (1452, 32774, 512), (1452, 33795, 38963)]
ioreg output saved to /tmp/ioreg.txt
Looking for BEBOOK
Looking for BEBOOK_MINI
Looking for BLACKBERRY
Looking for CYBOOKG3
Looking for EB600
Looking for ILIAD
Looking for IREXDR1000
Looking for JETBOOK
Looking for KINDLE
Looking for KINDLE2
Looking for KINDLE_DX
Looking for PRS500
Looking for PRS505
Looking for PRS700
Looking for ANDROID
Looking for CYBOOK_OPUS
Looking for COOL_ER
Looking for ESLICK
Device possibly connected: <calibre.devices.jetbook.driver.JETBOOK object at 0x55c4110>
Trying to open device... failed
Opening of the following devices failed
<calibre.devices.jetbook.driver.JETBOOK object at 0x55c4110>
Traceback (most recent call last):
File "/Applications/calibre.app/Contents/Resources/lib/python2.6/site-packages.zip/calibre/debug.py", line 113, in debug_device_driver
dev.open()
File "calibre/devices/usbms/device.pyo", line 574, in open
File "calibre/devices/usbms/device.pyo", line 357, in open_osx
DeviceError: Unable to detect the JETBOOK disk drive. Try rebooting.