Please read this carefully

This ONLY works on FW 6.72.

1. If you get a "There is not enough free system memory" message without any pop-ups, then it means that the webkit exploit has failed. Click OK and retry. This error is not going to harm your console. Success rate here is about 10%, so don't worry.
2. For advanced users: To load your own payloads using NetCat, run JB+NETCAT and send the payload to TCP port 9021 (9020 for the legacy version).

This exploit does crash and hang. Sometimes you even have to retry 10 times to get the jailbreak.

Credits: @theflow for vulnerability disclosure