Using the Onboard recorder, log files can be retrieved using the remote Codex UI. On the recorder check the software version at the top of the Setup->System screen (e.g. 2013.r1.2108). Then go to www.codexdigital.com/software and download the matching Codex UI version for Mac or Windows.
Set up a network connection between your computer and the Onboard recorder using the advice in sections 3.3 and 3.4 of this User Guide.
Then open the Codex UI software and enter the IP address for the recorder in the Connect To Server box. Now go to the SETUP tab and click the i button (lower-right) and use the SAVE LOGS button. Use the File Browser (folder icon) to choose a local directory on your computer to save the logs to.