I made it public if you guys want to fork it. It's a bit of a hot mess, as I used the townie AI to help write it.
You can view the source here:
https://www.val.town/v/synapticrobotics/RobotBackupCallGraph
Only one question, could you explain why backup.zip should not contain any directories?
For example, my MD backup creates the following folders (120iC, R30iB V9.10, created in Roboguide):
D:.
└───MNT_DATA
├───DLOG
├───MDB
├───MD_LS
├───RSCH
└───_BACKUP_
LS files are located in MD_LS, and the BACKDATE.DT is located in MDB.
So, what format does your MD backup have?