Ok, so at least the 'corrupted' 1.04 sd recovery image did not cause corruption in practise...
I created an alternative image now, that only formats the reader partition and flashes data and system partition with images from porkupans 1.04 restore package:
sdrescue_1.04_porkupan.7z (72.332.505 Bytes)
I also did some minor modifications that hopefully fix the reboot issue.