Yesterday I used Spirit to jailbreak my ipad and all went well. However, the first time I launched iBooks something peculiar happened. The display flashed for a moment, then redrew the iBooks "shelf" but missing was the button to show which PDFs were on the iPad. I resynced but the pdfs did not reappear. As a precaution I removed iBooks, then reinstalled iBooks and resynced. Still no pdfs in iBooks.