The restore proccess for a 1.9.x course will attempt to create a 2.x backup of the 1.9.x course first (an mbz) and then restore.
Have found that trying to use the Moodle 2 system for course restores only makes the DB larger, etc.
So, here's a work-around for LARGE courses - which depends upon MoodleMaster being able to do basic webmastering things:
1. create an 'xfer' folder at web root - OUTSIDE OF MOODLE. Set permissions on folder and the 1.9.x backups you will eventually place in there so that they can be read by the apache user/group.
2. upload the 1.9.x backups to that 'xfer' folder. The full URL to the backup can be copied to the clipboard of the workstation.
3. Go to your version 2. Turn ON URL repo.
4. Use restore link from any existing course, when choosing the file, use the URL repo. In the URL box, paste the URL to the backup file.
5. choose options for the restore ...
This gets around/by-passes the PHP file size upload.
It also might not be successful for a variety of reasons related to the 1.9 backup file itself.
In the moodledata directory there is a temp directory. Inside temp directory there will be a 'backup' directory. Successful restores will leave a 0 byte log file. Un-successful restores will live a .log file that is larger than 0 bytes and it list the various items the restore had issues with. That's your map for problems to address in the backup zip file.
Still, even if successful, if NOT choosing 'replace this course' as the option on restore, one will end up with "legacy" for the files contained in the course. That is NOT a physical folder anywhere by that name. Remember the new 2 file system uses the Moodle DB by default.
To be successful in getting *MOST* of a 1.9 backup to a 2, it's been my experience that the 2 needs to have same addons installed in the 2 previous to any attempt to restore. If an addon doesn't exist in the 2, that content will not be contained in the restored course. Other items may have issues ... the log file provides pointers.
'spirit of sharing', Ken