Hi Ronald,
If you are using the same version of SUM and target software components both for QA and the present environment, it should not be much issue except the fact that the directory HTDOCS contain information in the form of log files about how the entire process was executed till your downtime phase (like software components selected and execution time for each phase) for your DEV environement which you can't replace with the QA one. I'd suggest to reset the upgrade process after restoring the QA directories and see how it progresses.
Thanks