General Description:
The JTAG USERCODE cannot be read after I set read protection for the 18V00 or Platform Flash XCF PROMs.
This problem has been fixed in the latest 6.2i Service Pack, available at:
http://support.xilinx.com/xlnx/xil_sw_updates_home.jsp
The first service pack containing the fix is 6.2i Service Pack 1.