diff --git a/fuzzers/030-iob18/Makefile b/fuzzers/030-iob18/Makefile
index f90dbfd95..33120252e 100644
--- a/fuzzers/030-iob18/Makefile
+++ b/fuzzers/030-iob18/Makefile
@@ -5,7 +5,7 @@
 # https://opensource.org/licenses/ISC
 #
 # SPDX-License-Identifier: ISC
-N := 80
+N := 40
 SPECIMENS_DEPS := build/iobanks.txt
 include ../fuzzer.mk
 
@@ -23,6 +23,9 @@ build/segbits_riob18.db: build/segbits_riob18.rdb process_rdb.py bits.dbf
 	sed '/IOB18.IOB_Y1.LVDS/d' -i build/segbits_riob18.rdb
 	python3 process_rdb.py build/segbits_riob18.rdb > build/segbits_riob18_processed.rdb
 	${XRAY_DBFIXUP} --db-root build --zero-db bits.dbf --groups tag_groups.txt --seg-fn-in build/segbits_riob18_processed.rdb --seg-fn-out $@
+	# TODO: This is a hack. See https://github.com/f4pga/prjxray/issues/2073
+	echo 'RIOB18.IOB_Y0.SSTL12_SSTL135_SSTL15.IN !38_126 39_127' >> $@
+	sort -o $@ $@
 	${XRAY_MASKMERGE} build/mask_riob18.db $$(find -name segdata_riob18.txt)
 
 build/segbits_hclk_ioi.rdb: $(SPECIMENS_OK)
diff --git a/fuzzers/030-iob18/generate.py b/fuzzers/030-iob18/generate.py
index fc0af32c4..a4ac6356e 100644
--- a/fuzzers/030-iob18/generate.py
+++ b/fuzzers/030-iob18/generate.py
@@ -39,7 +39,7 @@ def drives_for_iostandard(iostandard):
     return drives
 
 STEPDOWN_IOSTANDARDS   = LVCMOS + SSTL
-IBUF_LOW_PWR_SUPPORTED = LVDS + DIFF_SSTL
+IBUF_LOW_PWR_SUPPORTED = LVDS + SSTL
 ONLY_DIFF_IOSTANDARDS  = LVDS
 
 
diff --git a/fuzzers/030-iob18/top.py b/fuzzers/030-iob18/top.py
index e8f39805d..6944e1ca3 100644
--- a/fuzzers/030-iob18/top.py
+++ b/fuzzers/030-iob18/top.py
@@ -65,6 +65,15 @@ def run():
         "SSTL12":  DIFF_SSTL12,
     }
 
+    vref_map = {
+        "SSTL12":        .600,
+        "SSTL135":       .675,
+        "SSTL15":        .75,
+        "DIFF_SSTL12":   .600,
+        "DIFF_SSTL135":  .675,
+        "DIFF_SSTL15":   .75,
+    }
+
     only_diff_map = {
         "LVDS": ["LVDS"],
     }
@@ -99,13 +108,7 @@ def run():
     for iobank in iobanks:
         iostandard = random.choice(iostandards)
         if iostandard in SSTL:
-            params['INTERNAL_VREF'][iobank] = random.choice(
-                (
-                    .600,
-                    .675,
-                    .75,
-                    .90,
-                ))
+            params['INTERNAL_VREF'][iobank] = vref_map[iostandard]
 
         iostandard_map[iobank] = iostandard
 
diff --git a/fuzzers/030-iob18/write_io_banks.tcl b/fuzzers/030-iob18/write_io_banks.tcl
index eac330dab..aca8c1d01 100644
--- a/fuzzers/030-iob18/write_io_banks.tcl
+++ b/fuzzers/030-iob18/write_io_banks.tcl
@@ -11,7 +11,10 @@ open_io_design -name io_1
 set fp [open "iobanks.txt" "w"]
 foreach iobank [get_iobanks] {
     foreach site [get_sites -of $iobank] {
-        puts $fp "$site,$iobank"
+        # we only care about the high performance banks here
+        if {[string match "BT_HIGH_PERFORMANCE" [get_property BANK_TYPE $iobank]]} {
+            puts $fp "$site,$iobank"
+        }
     }
 }
 close $fp
diff --git a/utils/bit2fasm.py b/utils/bit2fasm.py
index 103b377ef..859ec1096 100755
--- a/utils/bit2fasm.py
+++ b/utils/bit2fasm.py
@@ -91,7 +91,7 @@ def main():
         '--part', help="Name of part being targetted.", **part_kwargs)
     parser.add_argument(
         '--bitread',
-        help="Name of part being targetted.",
+        help="bitread tool to to use",
         default=default_bitread)
     parser.add_argument(
         '--frame_range', help="Frame range to use with bitread.")