uboot, the non working card was completely empty - but the one that did work was not empty.
I don't think the system image was corrupted - tried several times, in each I copied the folder to the formatted card.
I tried to format the card as FAT, FAT32 and NTFS - all with default allocation unit size - none of them worked (The working SD card was formatted as FAT).
About the chkdsk - I am not sure about what I did - if you want anything else please explain how to do so (I am not very familiar with that area).
