USRP 2 SD Card reprogram

Hi

I have been trying to update the firmware on my USRP2 device. Used the

https://ettus-apps.sourcerepo.com/redmine/ettus/projects/uhd/repository/revisions/master/changes/host/utils/usrp2_card_burner.py
https://ettus-apps.sourcerepo.com/redmine/ettus/projects/uhd/repository/revisions/master/changes/host/utils/usrp2_card_burner_gui.py

tools and the necessary and the images supplied on the website but i
keep getting

error: dd: opening ‘/dev/sdb’: Permission denied

can someone please help me with that

Regards

Syed