diff --git a/techlibs/nanoxplore/io_map.v b/techlibs/nanoxplore/io_map.v
index 42fac461903..edbb0437b11 100644
--- a/techlibs/nanoxplore/io_map.v
+++ b/techlibs/nanoxplore/io_map.v
@@ -6,3 +6,10 @@ module \$__BEYOND_OBUF (output PAD, input I);
 	NX_IOB_O _TECHMAP_REPLACE_ (.IO(PAD), .I(I), .C(1'b1));
 endmodule
 
+module \$__BEYOND_TOBUF (output PAD, input I, input C);
+	NX_IOB _TECHMAP_REPLACE_ (.IO(PAD), .I(I), .C(C));
+endmodule
+
+module \$__BEYOND_IOBUF (output PAD, input I, output O, output C);
+	NX_IOB _TECHMAP_REPLACE_ (.IO(PAD), .I(I), .O(O), .C(C));
+endmodule
diff --git a/techlibs/nanoxplore/synth_nanoxplore.cc b/techlibs/nanoxplore/synth_nanoxplore.cc
index 3842877e433..52d0256031e 100644
--- a/techlibs/nanoxplore/synth_nanoxplore.cc
+++ b/techlibs/nanoxplore/synth_nanoxplore.cc
@@ -292,10 +292,10 @@ struct SynthNanoXplorePass : public ScriptPass
 				run("nx_carry");
 			}
 			if (help_mode || iopad) {
-				run("iopadmap -bits -outpad $__BEYOND_OBUF I:PAD -inpad $__BEYOND_IBUF O:PAD A:top", "(only if '-iopad')");
+				run("iopadmap -bits -outpad $__BEYOND_OBUF I:PAD -toutpad $__BEYOND_TOBUF C:I:PAD -inpad $__BEYOND_IBUF O:PAD -tinoutpad $__BEYOND_IOBUF C:O:I:PAD A:top", "(only if '-iopad')");
 				run("techmap -map +/nanoxplore/io_map.v");
-				run("attrmvcp -attr LOC t:NX_IOB_O n:*");
-				run("attrmvcp -attr LOC -driven t:NX_IOB_I n:*");
+				run("attrmvcp -attr LOC t:NX_IOB_O t:NX_IOB n:*");
+				run("attrmvcp -attr LOC -driven t:NX_IOB_I t:NX_IOB n:*");
 			}
 			run("opt -fast");
 		}
diff --git a/tests/arch/nanoxplore/tribuf.ys b/tests/arch/nanoxplore/tribuf.ys
index c72e2e1ad5e..e55764f0126 100644
--- a/tests/arch/nanoxplore/tribuf.ys
+++ b/tests/arch/nanoxplore/tribuf.ys
@@ -4,9 +4,10 @@ proc
 tribuf
 flatten
 synth
-equiv_opt -assert -map +/nanoxplore/cells_sim.v -map +/simcells.v synth_nanoxplore # equivalency check
+equiv_opt -assert -map +/nanoxplore/cells_sim.v -map +/simcells.v synth_nanoxplore -iopad # equivalency check
 design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
 cd tristate # Constrain all select calls below inside the top module
 #Internal cell type used. Need support it.
-select -assert-count 1 t:$_TBUF_
-select -assert-none t:$_TBUF_ %% t:* %D
+select -assert-count 1 t:NX_IOB
+select -assert-count 2 t:NX_IOB_I
+select -assert-none t:NX_IOB t:NX_IOB_I %% t:* %D