diff --git a/fuzzers/011-clb-ffconfig/top.py b/fuzzers/011-clb-ffconfig/top.py
index 8cbd569b..fc94997d 100644
--- a/fuzzers/011-clb-ffconfig/top.py
+++ b/fuzzers/011-clb-ffconfig/top.py
@@ -18,7 +18,7 @@ from prims import *
 # 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)
+CLBN = 200 + int(INCREMENT)
 print('//Requested CLBs: %s' % str(CLBN))
 
 f = open("top.txt", "w")
diff --git a/fuzzers/014-clb-ffsrcemux/top.py b/fuzzers/014-clb-ffsrcemux/top.py
index 4040e71c..bcdfed84 100644
--- a/fuzzers/014-clb-ffsrcemux/top.py
+++ b/fuzzers/014-clb-ffsrcemux/top.py
@@ -18,7 +18,7 @@ from prjxray import verilog
 # 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)
+CLBN = 200 + int(INCREMENT)
 print('//Requested CLBs: %s' % str(CLBN))
 
 
diff --git a/fuzzers/015-clb-nffmux/generate.sh b/fuzzers/015-clb-nffmux/generate.sh
index bfda796b..320acf71 100644
--- a/fuzzers/015-clb-nffmux/generate.sh
+++ b/fuzzers/015-clb-nffmux/generate.sh
@@ -8,6 +8,6 @@
 # SPDX-License-Identifier: ISC
 
 set -ex
-if [ $(${XRAY_VIVADO} -h |grep Vivado |cut -d\  -f 2) != "v2017.2" ] ; then echo "FIXME: requires Vivado 2017.2. See https://github.com/SymbiFlow/prjxray/issues/14"; exit 1; fi
+# (v7: gate disabled, 2020.1 required) if [ $(${XRAY_VIVADO} -h |grep Vivado |cut -d\  -f 2) != "v2017.2" ] ; then echo "FIXME: requires Vivado 2017.2. See https://github.com/SymbiFlow/prjxray/issues/14"; exit 1; fi
 source ${XRAY_DIR}/utils/top_generate.sh
 
diff --git a/fuzzers/015-clb-nffmux/top.py b/fuzzers/015-clb-nffmux/top.py
index 777b5480..b21c420a 100644
--- a/fuzzers/015-clb-nffmux/top.py
+++ b/fuzzers/015-clb-nffmux/top.py
@@ -16,7 +16,7 @@ from prjxray import verilog
 # 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)
+CLBN = 200 + int(INCREMENT)
 print('//Requested CLBs: %s' % str(CLBN))
 
 
diff --git a/fuzzers/016-clb-noutmux/generate.sh b/fuzzers/016-clb-noutmux/generate.sh
index bfda796b..320acf71 100644
--- a/fuzzers/016-clb-noutmux/generate.sh
+++ b/fuzzers/016-clb-noutmux/generate.sh
@@ -8,6 +8,6 @@
 # SPDX-License-Identifier: ISC
 
 set -ex
-if [ $(${XRAY_VIVADO} -h |grep Vivado |cut -d\  -f 2) != "v2017.2" ] ; then echo "FIXME: requires Vivado 2017.2. See https://github.com/SymbiFlow/prjxray/issues/14"; exit 1; fi
+# (v7: gate disabled, 2020.1 required) if [ $(${XRAY_VIVADO} -h |grep Vivado |cut -d\  -f 2) != "v2017.2" ] ; then echo "FIXME: requires Vivado 2017.2. See https://github.com/SymbiFlow/prjxray/issues/14"; exit 1; fi
 source ${XRAY_DIR}/utils/top_generate.sh
 
diff --git a/fuzzers/016-clb-noutmux/top.py b/fuzzers/016-clb-noutmux/top.py
index f6f33a8f..5ed5127c 100644
--- a/fuzzers/016-clb-noutmux/top.py
+++ b/fuzzers/016-clb-noutmux/top.py
@@ -16,7 +16,7 @@ from prjxray import verilog
 # 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)
+CLBN = 200 + int(INCREMENT)
 print('//Requested CLBs: %s' % str(CLBN))