util-linux in current breaks usbimg2disk.sh
 

The meaning of the -A switch to sfdisk has changed in the latest util-linux package. This causes the call to makebootable() in usbimg2disk.sh to hang. I think it now needs to be a lower case -a ( activate partition ).

Thanks for posting this. I was about to post the problem of usbimg2disk.sh hanging, & found this post when I searched for similar problems.
Regards,
Bill