diff --git a/fuzzers/018-clbram/Makefile b/fuzzers/018-clbram/Makefile
index f5f5a631..a28b0d4b 100644
--- a/fuzzers/018-clbram/Makefile
+++ b/fuzzers/018-clbram/Makefile
@@ -1,3 +1,4 @@
 N := 1
+SLICEL ?= N
 include ../clb.mk
 
diff --git a/fuzzers/019-ndi1mux/Makefile b/fuzzers/019-ndi1mux/Makefile
index 6f7ac88d..a28b0d4b 100644
--- a/fuzzers/019-ndi1mux/Makefile
+++ b/fuzzers/019-ndi1mux/Makefile
@@ -1,31 +1,4 @@
-# clb.mk clblm only
-
 N := 1
-SPECIMENS := $(addprefix build/specimen_,$(shell seq -f '%03.0f' $(N)))
-SPECIMENS_OK := $(addsuffix /OK,$(SPECIMENS))
-
-database: $(SPECIMENS_OK)
-	${XRAY_SEGMATCH} -o build/segbits_clblx.db $(addsuffix /segdata_clblm_[lr].txt,$(SPECIMENS))
-
-pushdb:
-	${XRAY_MERGEDB} clblm_l build/segbits_clblx.db
-	${XRAY_MERGEDB} clblm_r build/segbits_clblx.db
-
-build:
-	mkdir build
-
-$(SPECIMENS_OK): build
-	bash generate.sh $(subst /OK,,$@)
-	touch $@
-
-run:
-	$(MAKE) clean
-	$(MAKE) database
-	$(MAKE) pushdb
-	touch run.ok
-
-clean:
-	rm -rf build
-
-.PHONY: database pushdb run clean
+SLICEL ?= N
+include ../clb.mk
 
diff --git a/fuzzers/clb.mk b/fuzzers/clb.mk
index 97f9a140..139a625b 100644
--- a/fuzzers/clb.mk
+++ b/fuzzers/clb.mk
@@ -1,12 +1,17 @@
 N ?= 1
-DBFIXUP ?=
+CLB_DBFIXUP ?=
+SLICEL ?= Y
 
 include ../fuzzer.mk
 
 database: build/segbits_clbx.db
 
 build/segbits_clbx.rdb: $(SPECIMENS_OK)
+ifeq ($(SLICEL),Y)
 	${XRAY_SEGMATCH} -o build/segbits_clbx.rdb $(addsuffix /segdata_clbl[lm]_[lr].txt,$(SPECIMENS))
+else
+	${XRAY_SEGMATCH} -o build/segbits_clbx.rdb $(addsuffix /segdata_clblm_[lr].txt,$(SPECIMENS))
+endif
 
 build/segbits_clbx.db: build/segbits_clbx.rdb
 ifeq ($(CLB_DBFIXUP),Y)
@@ -16,9 +21,10 @@ else
 endif
 
 pushdb:
-	$(DBFIXUP)
+ifeq ($(SLICEL),Y)
 	${XRAY_MERGEDB} clbll_l build/segbits_clbx.db
 	${XRAY_MERGEDB} clbll_r build/segbits_clbx.db
+endif
 	${XRAY_MERGEDB} clblm_l build/segbits_clbx.db
 	${XRAY_MERGEDB} clblm_r build/segbits_clbx.db