Comment 5 for bug 722019

I wasn't one of the reporters of this bug, but I found this bug because I've been seeing the exact same problem. I tried your suggestion (Jordon) of passing "--allow-system-internal" to usb-creator-gtk (0.2.23) and it does indeed seem to allow the bootloader installation to succeed where it was previously failing.

BTW, the "polkit" authorisation dialogs come up at least 3 times during the process of creating the USB device, which can make you think that perhaps the process is borked and trying to do something it wasn't originally authorised to do (like write a bootloader to the hard-drive instead of the USB device). Is there any way things could be improved to not require multiple authorisation steps? For one thing, it encourages a click-through mentality that will sooner or later catch someone out. Anyway, that's just general feedback.

But, yeah - the --allow-system-internal workaround seems to work for me.