Retrieving keybags for image DeviceTree.d221ap.im4p
[e] cannot get keybag
[GM] Keybag extraction failed. maybe you forgot to --download?
[GM] Retrieving keybags for image LLB.d22.RELEASE.im4p
[GM] Retrieving keybags for image iBoot.d22.RELEASE.im4p
[GM] Retrieving keybags for image iBEC.d22.RELEASE.im4p
[GM] Retrieving keybags for image iBSS.d22.RELEASE.im4p
[GM] Done!
[GM] running keybag decryption...
[GM] Waiting for DFU device to appear.Traceback (most recent call last):
  File "./grandmaster.py", line 472, in <module>
    main()
  File "./grandmaster.py", line 439, in main
    handleKBAGDecryption()
  File "./grandmaster.py", line 225, in handleKBAGDecryption
    waitForDFUAndPWN()
  File "./grandmaster.py", line 202, in waitForDFUAndPWN
    USBserialStr = deviceFinderObj.findAllUSBDevices()
  File "/Users/alexandrejacq/Documents/SSEC/grandmaster/devicefinder.py", line 90, in findAllUSBDevices
    dev_recovery_mode = usb.core.find(idProduct=0x1281)
  File "/usr/local/lib/python3.7/site-packages/usb/core.py", line 1263, in find
    raise NoBackendError('No backend available')
usb.core.NoBackendError: No backend available
sh-3.2#