OTHER PTOOL SETTINGS: Isaac has reported that he's not checking anything except the 24pN and "C" settings. No "3rd party battery", no MJPEG, etc. Svart, have you tested while unchecking settings like battery, MJPEG, etc.? Isaac asked you this and I’ve not seen an answer. This could be an issue.
I posted my test results earlier in this thread and I think they should be pretty clear that I found that ONLY enabling the Native 24p patch by itself was enough to elicit the failures. I didn't have to change anything else.
In short, I open Ptool, click native 24p (and version check) and load the firmware into the camera. I point it at the star chart or at the grass in my yard and within a few seconds I get the card speed error. I don't change the bitrates or anything else.