Yeah, the problem is solved! Like I thought the problem was the old uboot version of my device. After I updated the uboot to newest universal 0.6 version, I made a new sd-card with the generic 2GB RAM-1GBIT ETHERNET dtb file and rebooted to recovery. Now version 7.03.012c works like a charm!
Where can I find this universal uboot 0.6 version? Thanks!