diff --git a/fuzzers/011-clb-ffconfig/top.py b/fuzzers/011-clb-ffconfig/top.py
index 87106984..e403081a 100644
--- a/fuzzers/011-clb-ffconfig/top.py
+++ b/fuzzers/011-clb-ffconfig/top.py
@@ -1,11 +1,14 @@
-import random
+import os, random
 random.seed(0)
 from prjxray import util
 from prjxray import verilog
 
 from prims import *
 
-CLBN = 600
+# INCREMENT is the amount of additional CLBN to be instantiated in the design.
+# This makes the fuzzer compilation more robust against failures.
+INCREMENT = os.getenv('CLBN', 0)
+CLBN = 600 + int(INCREMENT)
 print('//Requested CLBs: %s' % str(CLBN))
 
 f = open("top.txt", "w")
diff --git a/fuzzers/012-clb-n5ffmux/top.py b/fuzzers/012-clb-n5ffmux/top.py
index 8d2ec5d9..a2be2d3d 100644
--- a/fuzzers/012-clb-n5ffmux/top.py
+++ b/fuzzers/012-clb-n5ffmux/top.py
@@ -1,9 +1,12 @@
-import random
+import os, random
 random.seed(0)
 from prjxray import util
 from prjxray import verilog
 
-CLBN = 40
+# INCREMENT is the amount of additional CLBN to be instantiated in the design.
+# This makes the fuzzer compilation more robust against failures.
+INCREMENT = os.getenv('CLBN', 0)
+CLBN = 40 + int(INCREMENT)
 print('//Requested CLBs: %s' % str(CLBN))
 
 
diff --git a/fuzzers/013-clb-ncy0/top.py b/fuzzers/013-clb-ncy0/top.py
index 1510ca77..65949a7f 100644
--- a/fuzzers/013-clb-ncy0/top.py
+++ b/fuzzers/013-clb-ncy0/top.py
@@ -1,9 +1,12 @@
-import random
+import os, random
 random.seed(0)
 from prjxray import util
 from prjxray import verilog
 
-CLBN = 400
+# INCREMENT is the amount of additional CLBN to be instantiated in the design.
+# This makes the fuzzer compilation more robust against failures.
+INCREMENT = os.getenv('CLBN', 0)
+CLBN = 400 + int(INCREMENT)
 print('//Requested CLBs: %s' % str(CLBN))
 
 
@@ -107,7 +110,7 @@ module clb_NCY0_O5 (input clk, input [7:0] din, output [7:0] dout);
     always @(*) begin
         s = din[7:4];
         s[N] = o6;
-        
+
         di = {din[3:0]};
         di[N] = o5;
     end
diff --git a/fuzzers/014-clb-ffsrcemux/top.py b/fuzzers/014-clb-ffsrcemux/top.py
index f56c3029..e0112629 100644
--- a/fuzzers/014-clb-ffsrcemux/top.py
+++ b/fuzzers/014-clb-ffsrcemux/top.py
@@ -5,7 +5,10 @@ import re
 from prjxray import util
 from prjxray import verilog
 
-CLBN = 600
+# INCREMENT is the amount of additional CLBN to be instantiated in the design.
+# This makes the fuzzer compilation more robust against failures.
+INCREMENT = os.getenv('CLBN', 0)
+CLBN = 600 + int(INCREMENT)
 print('//Requested CLBs: %s' % str(CLBN))
 
 
diff --git a/fuzzers/015-clb-nffmux/top.py b/fuzzers/015-clb-nffmux/top.py
index d233b89f..90769867 100644
--- a/fuzzers/015-clb-nffmux/top.py
+++ b/fuzzers/015-clb-nffmux/top.py
@@ -1,9 +1,12 @@
-import random
+import os, random
 random.seed(0)
 from prjxray import util
 from prjxray import verilog
 
-CLBN = 400
+# INCREMENT is the amount of additional CLBN to be instantiated in the design.
+# This makes the fuzzer compilation more robust against failures.
+INCREMENT = os.getenv('CLBN', 0)
+CLBN = 400 + int(INCREMENT)
 print('//Requested CLBs: %s' % str(CLBN))
 
 
diff --git a/fuzzers/016-clb-noutmux/top.py b/fuzzers/016-clb-noutmux/top.py
index 4cc660c0..808ef73c 100644
--- a/fuzzers/016-clb-noutmux/top.py
+++ b/fuzzers/016-clb-noutmux/top.py
@@ -1,9 +1,12 @@
-import random
+import os, random
 random.seed(0)
 from prjxray import util
 from prjxray import verilog
 
-CLBN = 400
+# INCREMENT is the amount of additional CLBN to be instantiated in the design.
+# This makes the fuzzer compilation more robust against failures.
+INCREMENT = os.getenv('CLBN', 0)
+CLBN = 400 + int(INCREMENT)
 print('//Requested CLBs: %s' % str(CLBN))
 
 
diff --git a/fuzzers/017-clb-precyinit/top.py b/fuzzers/017-clb-precyinit/top.py
index 348ec7e4..2edb311c 100644
--- a/fuzzers/017-clb-precyinit/top.py
+++ b/fuzzers/017-clb-precyinit/top.py
@@ -5,7 +5,10 @@ import re
 from prjxray import verilog
 from prjxray import util
 
-CLBN = 400
+# INCREMENT is the amount of additional CLBN to be instantiated in the design.
+# This makes the fuzzer compilation more robust against failures.
+INCREMENT = os.getenv('CLBN', 0)
+CLBN = 400 + int(INCREMENT)
 SLICEX, SLICEY = util.site_xy_minmax([
     'SLICEL',
     'SLICEM',
diff --git a/fuzzers/018-clb-ram/top.py b/fuzzers/018-clb-ram/top.py
index a7a02280..c96db4d7 100644
--- a/fuzzers/018-clb-ram/top.py
+++ b/fuzzers/018-clb-ram/top.py
@@ -15,12 +15,15 @@ SRLC32E_N
 Note: LUT6 was added to try to simplify reduction, although it might not be needed
 '''
 
-import random
+import os, random
 random.seed(0)
 from prjxray import util
 from prjxray import verilog
 
-CLBN = 50
+# INCREMENT is the amount of additional CLBN to be instantiated in the design.
+# This makes the fuzzer compilation more robust against failures.
+INCREMENT = os.getenv('CLBN', 0)
+CLBN = 50 + int(INCREMENT)
 print('//Requested CLBs: %s' % str(CLBN))
 
 
diff --git a/fuzzers/019-clb-ndi1mux/top.py b/fuzzers/019-clb-ndi1mux/top.py
index 5966a563..f9ce5224 100644
--- a/fuzzers/019-clb-ndi1mux/top.py
+++ b/fuzzers/019-clb-ndi1mux/top.py
@@ -1,9 +1,12 @@
-import random
+import os, random
 random.seed(0)
 from prjxray import util
 from prjxray import verilog
 
-CLBN = 50
+# INCREMENT is the amount of additional CLBN to be instantiated in the design.
+# This makes the fuzzer compilation more robust against failures.
+INCREMENT = os.getenv('CLBN', 0)
+CLBN = 50 + int(INCREMENT)
 print('//Requested CLBs: %s' % str(CLBN))