There are 16 different versions of firmware that start with 073.
The oldest is the one on the drivers page for the device on Xerox.com, which would be 073.010.075.34540, which was compiled in late December 2015.
The newest version is 073.010.048.15000 and was compiled late May 2018, it is the one you get from Xerox.com/security.
Neither of them restrict USB print in any way, which would imply that either the issue is not related to the update, or that the update was done wrong (Not an Altboot or via the Tool installer).
If you can print from the USB while logged in as admin, then you would need to look into the permissions in CWIS for the non logged in user.
If it was a poorly done upgrade (Installed by CWIS or had a clone file loaded on it) you may get away with simply updating the firmware via the tool method. Failing that an Altboot no data backup no clone would be the fix, which would require a technician
Our Xerox workcentre 7830 has just been updated to the latest firmware updated from 72 to ConnectKey 73 and now won't print from USB it comes up with a message "user permissions restrict printing this job" basically I have jpeg on a usb and it now won't print.. where as before update NO PROBLEMS whatsoever! Help!!