> On the behavior I was thinking that the problem might be hardware so form my
> experience the series resistors between processor and sd card socket of 32
> ohm sometimes are to high for SPI so I tried to put some 10 ohms in parallel .
Well, considering the short lines and low loading I don't think those resistors can cause significant signal degradation, and they will protect the Pi against various card faults. Still, they aren't in the spec. You might try jumpering them all since you have the tools for working on SMD. It seems to me that there should be pullups on those lines, though, if only for static protection (see
http://www.flashgenie.net/img/productma ... 2final.pdf
Do any cameras and/or phones use the SPI mode? It occurs to me that the Chinese clone makers might not bother to implement it properly if it is not used in common consumer products.
I know that the boot code is proprietary but does the foundation have access to the source? Since the card interface seems to be pure bit-banging that may be where the bug is.
It would be interesting (though difficult for obvious reasons) to learn how well the current Linux driver works with the troublesome cards (I know it works fine with mine).