When I create an SVF file from an encrypted bitstream using iMPACT, the SVF file does not correctly configure the device. However, the encrypted ".bit" file configures the device correctly.
Normally, iMPACT resets the JTAG TAP state before loading the CFG_IN instruction. This reset sequence is not reflected in the SVF. You can work around this issue for the Virtex-II SVF by inserting a "STATE RESET;" command before every instance in which the CFG_IN instruction is loaded. You can obtain a Perl script for this purpose by contacting the Xilinx Technical Support at:
The SVF2XSVF translator cannot handle the order of commands in the SVF for the encrypted bitstreams. To work around this problem, use the -xwait option. If separate SVF files for the key and bit file exist, use the -xwait option for both conversions to XSVF. This issue is resolved with the latest SVF2XSVF translator. (V5.02)
svf2xsvf501 -d -fpga -extensions -xwait -i key.svf -o key.xsvf
svf2xsvf501 -d -fpga -extensions -xwait -i bit_fixed.svf -o bit_fixed.xsvf