diff --git a/iverilog.conf b/iverilog.conf
index 695ea6760..dd64dd21a 100644
--- a/iverilog.conf
+++ b/iverilog.conf
@@ -72,7 +72,7 @@
 # These rules support synthesized and non-synthesized variants.
 
 [-tvvp -S]
-<ivl>%B/ivl %[v-v] -C%C %g %W %s %[M-M%M] %[N-N%N] %[T-T%T] -tdll -fDLL=%B/vvp.tgt -fVVP_EXECUTABLE=%B/../../bin/vvp -Fsynth -Fsyn-rules -Fcprop -Fnodangle %f %m -o%o -- -
+<ivl>%B/ivl %[v-v] -C%C %g %W %s %[M-M%M] %[N-N%N] %[T-T%T] -tdll -fDLL=%B/vvp.tgt -fVVP_EXECUTABLE=%B/../../bin/vvp -Fsynth2 -Fsynth -Fsyn-rules -Fcprop -Fnodangle %f %m -o%o -- -
 
 [-tvvp]
 <ivl>%B/ivl %[v-v] -C%C %g %W %s %[M-M%M] %[N-N%N] %[T-T%T] -tdll -fDLL=%B/vvp.tgt -fVVP_EXECUTABLE=%B/../../bin/vvp -Fcprop -Fnodangle %f %m -o%o -- -
@@ -90,11 +90,11 @@
 # This is the XNF code generator.
 
 [-txnf]
-<ivl>%B/ivl -C%C %[v-v] %g %s %[M-M%M] %[N-N%N] %[T-T%T] -txnf -Fsynth -Fsyn-rules -Fxnfio -Fcprop -Fnodangle -o%o -- -
+<ivl>%B/ivl -C%C %[v-v] %g %s %[M-M%M] %[N-N%N] %[T-T%T] -txnf -Fsynth2 -Fsynth -Fsyn-rules -Fxnfio -Fcprop -Fnodangle -o%o -- -
 
 # And this is another XNF code generator, under development.
 [-tfpga]
-<ivl>%B/ivl -C%C %[v-v] %g %s %[M-M%M] %[N-N%N] %[T-T%T] %f -tdll -fDLL=%B/fpga.tgt -Fsynth -Fsyn-rules -Fcprop -Fnodangle -o%o -- -
+<ivl>%B/ivl -C%C %[v-v] %g %s %[M-M%M] %[N-N%N] %[T-T%T] %f -tdll -fDLL=%B/fpga.tgt -Fsynth2 -Fsynth -Fsyn-rules -Fcprop -Fnodangle -o%o -- -
 
 # --
 # This is the pal code generator. The target module requires the -fpart=<type>