Backup the front page. That should give you an ID #1 folder in moodledata. Upload the 1.4G backup zip into the #1 folder by some other means: ftp, scp, etc..
Check ownership/permissions on the uploaded 1.4G backup zip to make sure web server user can see it.
Should be able to at least start the restore process ... although some further tweaking might be needed to restore such a large course ... php timeouts/limits, etc..
'spirit of sharing', Ken