Found an issue when trying to install a "kmod"-package from the official repository , looks like my .config was too different.
New start from "https://downloads.openwrt.org/releases/19.07.7/targets/ipq40xx/generic/config.buildinfo", make, wait, sysupgrade and issue is gone.
New build and SHA256 sums are here:
openwrt-19.07.7-ipq40xx-generic-avm_fritzbox-4040-squashfs-eva.bin
https://drive.google.com/file/d/19t3dMOuvQ34ehMuXRMtj8zEgdWV4zCXF/view?usp=sharing
17CDFF74E2A1C1215E0E96EFE5BC8526640FA6D5108EBBB1A19F93E0F77B9C2C
openwrt-19.07.7-ipq40xx-generic-avm_fritzbox-4040-squashfs-sysupgrade.bin
https://drive.google.com/file/d/1AXEBYrjTfEWav7uWvk6tHKXy3TGFyK2m/view?usp=sharing
3D77B5BA46033A12E197A0F1265561419924331DF04E80CC7296B0F0EABEE890
Cheers,
Thomas