Hi Tom,
In my case the culprit was /images/postdownloadscripts/fog.postdownload.
echo "Activating boot partition..." sfdisk --activate /dev/sda 1 echo "Rebooting..." reboot -fFix was simply commenting out (or deleting) those lines. After cleanup the file looks like this:
cat /images/postdownloadscripts/fog.postdownload #!/bin/bash ## This file serves as a starting point to call your custom postimaging scripts. ## <SCRIPTNAME> should be changed to the script you're planning to use. ## Syntax of post download scripts are #. ${postdownpath}<SCRIPTNAME>Thanks for the pointer, Tom — saved me from chasing GPT partition tables for a problem that had nothing to do with them.