diff --git a/fuzzers/036-iob18-ologic-sing/Makefile b/fuzzers/036-iob18-ologic-sing/Makefile
index dc34c29b..eb1f8048 100644
--- a/fuzzers/036-iob18-ologic-sing/Makefile
+++ b/fuzzers/036-iob18-ologic-sing/Makefile
@@ -13,7 +13,10 @@
 # nextpnr asks for OLOGIC features on SING-row LED IOBs (VC707
 # counter25 build hits this for led[?] @ LIOI_SING_X82Y51).
 
-N := 20
+# N=50: the sibling 036-iob18-ologic uses N=40 to resolve the OLOGIC_Y0
+# enum features (OMUX/OQUSED/OSERDES.DATA_RATE_TQ); SING needs at least as
+# many specimens or dbfixup drops them as unresolved/duplicate.
+N := 50
 include ../fuzzer.mk
 
 database: build/segbits_rioi_sing.db
diff --git a/fuzzers/036-iob18-ologic-sing/bits.dbf b/fuzzers/036-iob18-ologic-sing/bits.dbf
index 8e902b07..b9f8165a 100644
--- a/fuzzers/036-iob18-ologic-sing/bits.dbf
+++ b/fuzzers/036-iob18-ologic-sing/bits.dbf
@@ -1,6 +1,6 @@
-33_91 33_93
+33_27 33_29
 32_36 32_34
 33_61 32_58 33_57
-32_70 32_66 33_69
-30_95 30_99 30_127 31_126 31_124 30_121 31_120 30_123 31_116 31_100
-31_00 30_01 30_03 31_06 30_07 31_04 30_11 31_28 31_32 30_29 30_27
+32_6 32_2 33_5
+30_31 30_35 30_63 31_62 31_60 30_57 31_56 30_59 31_52 31_36
+31_0 30_1 30_3 31_6 30_7 31_4 30_11 31_28 31_32 30_29 30_27