From another post, I think the OP left the QC overnight to find it stuck next day at 70%: A thread for those who successfully updated to CorOS 3.0 - #146 by Kashi
From another post, I think the OP left the QC overnight to find it stuck next day at 70%: A thread for those who successfully updated to CorOS 3.0 - #146 by Kashi