Why the system goes without further testing back at Amazon:
1. The mp3 files of audio books are sorted from USB flash drive in random order.
Ordnerstrucktur Test1: USBSTICK: About Folders -> subfolder title Audiobook -> mp3 files of the audiobook with unique names.
Ordnerstrucktur Test2: USBSTICK: folder Title of audio book -> mp3 files of the audiobook with unique names.
All mp3 files have unique mp3 tags. The data were therefore not sorted either by day or by file name.
2. The system can not be put in standby mode.
My unit switches directly into the ECO mode instead of in standby. Unfortunately, settings can be programmed as system time and alarm function only from the standby mode.