The manual
http://passthrough.fw-notify.net/download/022630/http://www.rocktheboatmarine.co m/specs/MS-600.pdf
for the device says:
iPod TOP SLEEVE BOTTOM SLEEVE
classic, 5th Gen (30gb) A A
classic, 5th Gen (60/80gb) A B
classic, 6th Gen (80gb) B A
classic, 6th Gen (160gb) B B
classic, 7th Gen B A
touch, 1st Gen, 2nd Gen D D
nano, 2nd Gen C C
nano, 3rd Gen, + Adapter A A
nano, 4th Gen E E
Other F F
Note: To check your iPod model, go to www.apple.com/support
and enter the serial number found on the back of the iPod
Thus, if you`reset the boat system and did the following:
Try:
- Reset the iOS device. Nothing will be lost
Reset iOS device: Hold down the On/Off button and the Home button at the same time for at
least ten seconds, until the Apple logo appears.
- Reset all settings
Go to Settings > General > Reset and tap Reset All Settings.
All your preferences and settings are reset. Information (such as contacts and calendars) and media (such as songs and videos) aren’t affected.
- Restore from backup. See:
iOS: How to back up
- Restore to factory settings/new iOS device.
That would indicate it is not compatible with either the 4G iPod or iOS 6. Sometimes an iOS update breaks compatibility and there is nothing you can do.