I was preparing to replace the SD card on a W4400Nex yesterday and generally I will perform the 'restore all settings' prior to doing this. Never had an issue with doing 'restore all settings' but this time it just hung there. And hung. And hung. 30 minutes later I had no option but to turn the car off.
Subsequently when I powered on the radio it displayed the custom jpeg splash screen, stuck there for 30 seconds or so, came up with pioneer loading... Then it just repeated said cycle.
This was booting with the pre-swap SD card that was working prior except for am/fm missing an