All, I downloaded C8 Minimal image again (I think it's in fact 4th time when I re downloaded the image), wiped my "production" sd card and it works. Unbelievable that my other 2 sd cards worked fine with C7, did not work with C8. Might just throw those 2 away. Anyway, thank you for your effort in making the image and sorry about the trouble I caused. Regards, Marcin