diff --git a/fuzzers/036-iob-ologic/generate.py b/fuzzers/036-iob-ologic/generate.py
index d9445a5c..bda4cf5b 100644
--- a/fuzzers/036-iob-ologic/generate.py
+++ b/fuzzers/036-iob-ologic/generate.py
@@ -37,6 +37,8 @@ def main():
 
             handle_data_width(segmk, d)
 
+            segmk.add_site_tag(site, 'OSERDESE.IN_USE', d['use_oserdese2'])
+
             if d['use_oserdese2']:
                 segmk.add_site_tag(site, 'OQUSED', 1)
                 if 'SRTYPE' in d:
@@ -60,9 +62,11 @@ def main():
                     segmk.add_site_tag(site, 'Z' + opt, 1 ^ d[opt])
 
                 for opt in ['CLK', 'CLKDIV']:
-                    k = 'IS_{}_INVERTED'.format(opt)
-                    segmk.add_site_tag(site, k, d[k])
-                    segmk.add_site_tag(site, 'ZINV_{}'.format(opt), 1 ^ d[k])
+                    if d['{}_USED'.format(opt)]:
+                        k = 'IS_{}_INVERTED'.format(opt)
+                        segmk.add_site_tag(site, k, d[k])
+                        segmk.add_site_tag(
+                            site, 'ZINV_{}'.format(opt), 1 ^ d[k])
 
                 for idx in range(4):
                     k = 'IS_T{}_INVERTED'.format(idx + 1)
diff --git a/fuzzers/036-iob-ologic/generate.tcl b/fuzzers/036-iob-ologic/generate.tcl
index 85caab36..9cd70195 100644
--- a/fuzzers/036-iob-ologic/generate.tcl
+++ b/fuzzers/036-iob-ologic/generate.tcl
@@ -86,6 +86,7 @@ proc run {} {
     set_property CONFIG_VOLTAGE 3.3 [current_design]
     set_property BITSTREAM.GENERAL.PERFRAMECRC YES [current_design]
     set_property IS_ENABLED 0 [get_drc_checks {REQP-79}]
+    set_property IS_ENABLED 0 [get_drc_checks {REQP-144}]
 
     write_checkpoint -force design_pre_place.dcp
 
diff --git a/fuzzers/036-iob-ologic/top.py b/fuzzers/036-iob-ologic/top.py
index 2407fcf9..b55e5054 100644
--- a/fuzzers/036-iob-ologic/top.py
+++ b/fuzzers/036-iob-ologic/top.py
@@ -103,6 +103,16 @@ def use_oserdese2(p, luts, connects):
     p['IS_CLK_INVERTED'] = random.randint(0, 1)
     p['IS_CLKDIV_INVERTED'] = random.randint(0, 1)
 
+    clk_connections = ''
+    p['CLK_USED'] = random.randint(0, 1)
+    p['CLKDIV_USED'] = random.randint(0, 1)
+    if p['CLK_USED']:
+        clk_connections += '''
+        .CLK({}),'''.format(luts.get_next_output_net())
+    if p['CLKDIV_USED']:
+        clk_connections += '''
+        .CLKDIV({}),'''.format(luts.get_next_output_net())
+
     print(
         '''
     (* KEEP, DONT_TOUCH, LOC = "{ologic_loc}" *)
@@ -134,8 +144,7 @@ def use_oserdese2(p, luts, connects):
         .OQ({owire}),
         {TFB}
         {TQ}
-        .CLK({clknet}),
-        .CLKDIV({clkdivnet}),
+        {clk_connections}
         .D1({d1net}),
         .D2({d2net}),
         .D3({d3net}),
@@ -152,8 +161,7 @@ def use_oserdese2(p, luts, connects):
         .T4({t4net}),
         .TCE({tcenet})
         );'''.format(
-            clknet=luts.get_next_output_net(),
-            clkdivnet=luts.get_next_output_net(),
+            clk_connections=clk_connections,
             rstnet=luts.get_next_output_net(),
             d1net=luts.get_next_output_net(),
             d2net=luts.get_next_output_net(),