Building a data logging and transmission system here. I've a RedBearLab Blend with built-in BLE capabilities and a (cheap) SD / Data logging shield that looks very suspiciously like it's copied from the Adafruit one.
Using a Stock Arduino Uno board, the Data logging shield works out of the box - both RTC TimeSet and cardinfo come back successfully.
Stacking the shield on the Blend, both examples lead nowhere. The TimeSet states that no connection could be made, and the cardinfo says it can't find the card.
I assume it's a pin conflict of some sort, but I'm really unsure what I should do to debug/fix it.
 As I found out below, the SD Module works now - but I still face the problem of not getting the RTC to work. Neither on the shield nor a Tiny RTC module. Again, both work fine on the Arduino Uno.
[edit2] I had basically the same problem for the RTC module as well - see the answer below.