If you launch iBooks on a Jailbroken iPhone there’s a good chance you’ll get an error message and not be able to open any of your legitimately purchased iBooks content. This is NOT a new problem — many of us here at TiPb have been having this issue for a while and with older versions of iBooks. Some thought it was a bug with iBooks or an issue with certain releases of redsn0w or greenpois0n Jailbreak tools, but iPhone dev-team member @comex finally figured out what was causing it.
It seems that before opening a DRMed book, iBooks drops an improperly signed binary, tries to execute it, and if it works concludes that the device is jailbroken and refuses to open the book.
This is what the binary does:
int main() {
return 42;
}
The complete message you get is:
There is a problem with the configuration of your iPhone. Please restore […]
Read the original post by Brian Tufo