iDrac and LCC upgrades in Maintenance Mode

We are running a Poweredge T620 at work, and having a bit of difficulty upgrading its versions to a newer version. It's still running some variation of LCC 1.0 and iDrac 1.3. Our network security prevents us from using FTP for the update method, and though we were able to use a CD to update two of them, our current computers have CD/DVD reading and writing disabled, so we can't make another disc to update with. When trying to update using a USB, I believe I have the correct file to update with (firmimg.d7 for version 1.66.65), but the machine keeps saying "Invalid catalog location" or some such. This specifically occurs when trying to install the firmware with a blank file path, as any path that I type in will immediately say that the file path is invalid. I was wondering if there was a way to update the LCC or iDrac using a flash BIOS file through USB, or if there's an alternative method I have not yet tried. It is in maintenance mode, and won't leave it without the update, and my senior admin has convinced me the web interface will not permit any changes made through the iDrac web interface while in this mode.