Hi Karel.
Many thanks for taking the time to post the issue.
We’ve observed this ourselves with some SD cards, picking another brand seemed to fix the problem. Before suggesting you should go and buy another I think we should confirm the file checksums to ensure the download completed successfully without corruption.
The MD5 hash for the actual vPi-1.0.4.zip file downloaded should be: 49279327f58e3225294e1e29363896f3
Once extracted, there should be file named vPi-1.0.4.img.gz which should have an MD5 hash of: 02235ad069cc2d4c6ea7486c96059b2d
Finally, the actual image file for vPi, named vPi-1.0.4.img, should have an MD5 hash of: 613ed5c2b44d1c7f6615bea05bea80ce
If you could check these checksums against yours this would be a good start.
Hope this helps you on your way to the vPi fun.
Cheers,
Darren.
@dawoo