hi Nick,
Can you please paste the logs for the SETSYNC_PREP_STARTED.log or .eLG file here. That will be avilable in your /SUM/abap/log or /sum/java/log directories.
Also any other latest SUM logs. And one more thing to check is does the the SUM directory has full permission for your <SID>adm user and has created a new /SUM/ABAP/exenew or exe folder and verify under that if the new kernel is extracted if yes.
Let us know if your still facing the issue.
regards,
Ram