Whitepaper entitled “Implementing and Detecting a PCI Rootkit”. This paper discusses means of persisting a rootkit on a PCI device containing a flashable expansion ROM.
You can download it from the following link: https://packetstormsecurity.com/files/download/52288/Implementing_And_Detecting_A_PCI_Rootkit.pdf
Source: https://packetstormsecurity.com/files/52288/Implementing_And_Detecting_A_PCI_Rootkit.pdf.html