I tried to debug it.
The line below either returns an empty array, or one file element called "dummy".

FTPFile[] files = ftpClient.listFiles("/upgrade/upgrade/signimgs");

So the loop never ends. I waited like an hour.
What can be the issue?

I'm running macOS Mojave.

can you made a new version to support this if you have time ,thank you

Hi jcase, thank you very much for this SW.
Worked like a charm on MacOS and 01.04.0300 FW of Mavic Pro Platinum (Downgraded from 01.04.0500 first ;) )

I'm eager to know how this works in the first place, everyone is talking about a race in the update system.
What in particular are we racing against?
Why is there 2 races that must be won? Where does the privilege escalation take place?
Is there a problem with the DUML or its interpretation?
Is there a detailed Whitepaper on it or may you give me some pointers? Of course if you couldn't explain without getting too technical then still go ahead and I will still attempt to understand and possibly read up on Android internal workings.

Sincerely Yours,
Microwave89

It was my mistake to keep DUMLdore open in background, as you can see in log there's Couldn't open port, exiting though it didn't exited. Exploit was stuck at Race 1.
Used version: v1.1.1

Choose target port: (* suggested port)
        [1] COM3 : USB Serial Device (COM3)
        [E] Exit
Choose port: 1
Using Port: COM3
Couldn't open port, exiting
Sending upgrade command
Uploading payload 1
Exploiting
Race 1 has started

I'm really bad at visual layouts, and I don't know the markup language for .md

Can someone stepup and fix it?

I've tried to run
java -jar DUMLRacer.jar AC
with Windows 10 on my Mavic Pro with firmware 1.4.100 but I get this error:

AC Mode

Choose target port: (* suggested port)
[1] COM6 : USB Serial Device (COM6)
[E] Exit
Choose port: 1
Using Port: COM6
Sending upgrade command
Uploading payload 1
Exception in thread "main" java.net.ConnectException: Connection timed out: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at org.apache.commons.net.SocketClient._connect(SocketClient.java:243)
at org.apache.commons.net.SocketClient.connect(SocketClient.java:202)
at com.cunninglogic.dumlracer.Main.uploadFile(Main.java:343)
at com.cunninglogic.dumlracer.Main.main(Main.java:129)

Thank you for this tool, amazing work. Seemed to work fine on a 1.04.0100 board I bought to fix a Mavic. Many people will be able to rollback from this firmware.

The issue i ran into is the tool hangs on the second race, but if you leave it long enough it finishes .. the tool just never responds back and appears to be hung on 'Starting the second race'. In my case the (files.length == 0) was true, but the tool never recognized it and was stuck.

I wonder if adding winner = true; to line 271 will fix it.

Good evening. I"m trying to use DUMLRacer.jar to downgrade my Mavic Pro Platinum to 1.04.0100 and its not working.
1st, thanks
2nd, I know "nothing" about coding, scrips, etc. I followed a youtube video, but didn't work.
https://www.youtube.com/watch?v=ywUUoYcPvt8

I have done everything through the DOS prompt, but get to:
Choose target Port.
[1] COM4 : USB Serial Device (COM4)
[E] Exit.
When I choose the port by entering 1, I get the following prompt:
Choose target port: (* suggested port)
[1] COM4 : USB Serial Device (COM4)
[E] Exit
Choose port: 1
Using Port: COM4
Couldn't open port, exiting
Sending upgrade command

What is going wrong with my comm port? Says Couldn't open port, exiting.
I have my Mavic plugged in via USB. It is recognized by assistant 2 v1.1.2 and 1.2.0
Under device manager, it shows a comport appearing when I plug in the Mavic:
USB Serial Device (COM4)

Device is working properly.
9600 bits per second
Driver: Microsoft 6/21/2006. V 10.0.16299.15

This is my 4th or 5th attempt with the same results.
On the first attempt I got through successfully, and it said completed. I then restarted my Mavic and tried to use DUMLdore 1.14 to go back to 1.04.0100
However, I get this popup and it only exits and never does anything.

Unhandled exception has occurred in your application. If you click Continue, the application will ignore this error and attempt to continue. If you click Quit, the application will close immediately.

Could not load file or assembly ‘WinSCPnet, Version=1.3.7.7601. Culture=neutral. PublicKey Token=2271ec4a3c56dbf’ or one of its dependencies. The system cannot find the file specified.exception has occurred in your application. If you click Continue, the application will ignore this error and attempt to continue. If you click Quit, the application will close immediately.

Could not load file or assembly ‘WinSCPnet, Version=1.3.7.7601. Culture=neutral. PublicKey Token=2271ec4a3c56dbf’ or one of its dependencies. The system cannot find the file specified.

Any suggestions?
Thanks!!