Hello  Jim - I have reached out to our Zebra experts to see if there's an easier solution to your issue.

I would recommend a file sync rule to get the OS file down to the device that sync's out of operation hours or with minimal disruption.

You can then start the upgrades using a package or a script to launch the update at a later date.

install_system_update /sdcard/nameoffile.zip

You can use custom groups to see which devices have got specific versions e.g. filter criteria, Add device property, OEMVersion

I would echo Ross's suggestion. While Packages containing the .ZIP files and auto applying Post Install Scripts can be used, the MobiControl DB wasn't really designed for handling very large Package sizes. The File Sync based approach has worked incredibly well for us in our remote deployments, especially since File Sync rules can be applied to the dynamic Virtual Groups as Ross has called out, whereas Packages/Profiles can only be targeted at the primary folder structure. It's relatively easy to create a Virtual Group based around a current OEM version so that you can assign a firmware update to just the devices that need it. Since you mentioned that the devices are TC77s, you should also be able to restrict downloads of the large files to WiFi so you can reduce the hit on the data plan. 

In the future, Zebra has plans for a FOTA based approach for distributing OEM and LG updates and I believe you'll be able to administer their distribution through SOTI. 

- Sent from Gogo on DL83 CDG to ATL. Not even kidding!