diff --git a/minitests/iostandard/dump_iobs.tcl b/minitests/iostandard/dump_iobs.tcl
index 05767626..c00cfe09 100644
--- a/minitests/iostandard/dump_iobs.tcl
+++ b/minitests/iostandard/dump_iobs.tcl
@@ -24,8 +24,8 @@ proc dump_iobs {file_name} {
     close $fp
 }
 
-create_project -force -in_memory -name dump_iobs -part $::env(VIVADO_PART)
+create_project -force -in_memory -name dump_iobs -part $::env(PART)
 set_property design_mode PinPlanning [current_fileset]
 open_io_design -name io_1
 
-dump_iobs "iobs-$::env(VIVADO_PART).csv"
+dump_iobs "iobs-$::env(PART).csv"
diff --git a/minitests/iostandard/features/Makefile b/minitests/iostandard/features/Makefile
index 35e393b1..d8bf76b0 100644
--- a/minitests/iostandard/features/Makefile
+++ b/minitests/iostandard/features/Makefile
@@ -1,5 +1,4 @@
-PART?=xc7a50tfgg484-1
-VIVADO_PART?=$(PART)
+PART?=${XRAY_PART}
 
 BIT2FASM_ARGS= --part "$(XRAY_DIR)/database/$(XRAY_DATABASE)/$(PART)" --verbose
 
@@ -33,20 +32,20 @@ clean:
 	@rm -rf features.csv
 	@rm -rf results.json
 	@rm -rf unknown_bits.jl
-	@rm -rf iobs-$(VIVADO_PART).csv
+	@rm -rf iobs-$(PART).csv
 
-iobs-$(VIVADO_PART).csv: ../dump_iobs.tcl
-	env VIVADO_PART=$(VIVADO_PART) $(XRAY_VIVADO) -mode batch -source ../dump_iobs.tcl -nojournal -log dump_iobs.log
+iobs-$(PART).csv: ../dump_iobs.tcl
+	env PART=$(PART) $(XRAY_VIVADO) -mode batch -source ../dump_iobs.tcl -nojournal -log dump_iobs.log
 
-designs.ok: iobs-$(VIVADO_PART).csv generate.py
-	env VIVADO_PART=$(VIVADO_PART) python3 ./generate.py
+designs.ok: iobs-$(PART).csv generate.py
+	env PART=$(PART) python3 ./generate.py
 	touch designs.ok
 
 designs: designs.ok
 
 %.bit: %.v designs.ok ../syn+par.tcl
 	mkdir -p build-$(basename $@)
-	cd build-$(basename $@) && env PROJECT_NAME=$(basename $@) VIVADO_PART=${VIVADO_PART} $(XRAY_VIVADO) -mode batch -source ../../syn+par.tcl -nojournal -log ../$@.log
+	cd build-$(basename $@) && env PROJECT_NAME=$(basename $@) PART=${PART} $(XRAY_VIVADO) -mode batch -source ../../syn+par.tcl -nojournal -log ../$@.log
 	rm -rf *.backup.log
 
 %.fasm: %.bit
diff --git a/minitests/iostandard/features/generate.py b/minitests/iostandard/features/generate.py
index 33d87101..669c7737 100644
--- a/minitests/iostandard/features/generate.py
+++ b/minitests/iostandard/features/generate.py
@@ -26,7 +26,6 @@ def load_iob_sites(file_name):
     for site_data in data:
         iob_sites[site_data["clock_region"]].append(site_data)
 
-    print(data)
     return iob_sites
 
 
@@ -40,6 +39,7 @@ IOBUF_NOT_ALLOWED = [
 
 DIFF_MAP = {
     'SSTL135': 'DIFF_SSTL135',
+    'SSTL15':  'DIFF_SSTL15',
 }
 
 
@@ -56,10 +56,10 @@ def gen_iosettings():
         'LVCMOS33',
         'LVTTL',
         'SSTL135',
+        'SSTL15',
 
         # Those are available but not currently fuzzed.
         #        'SSTL135_R',
-        #        'SSTL15',
         #        'SSTL15_R',
         #        'SSTL18_I',
         #        'SSTL18_II',
@@ -111,7 +111,7 @@ def run():
     """
 
     # Load IOB data
-    iob_sites = load_iob_sites("iobs-{}.csv".format(os.getenv("VIVADO_PART")))
+    iob_sites = load_iob_sites("iobs-{}.csv".format(os.getenv("PART")))
 
     # Generate IOB site to package pin map and *M site to *S site map.
     site_to_pkg_pin = {}
@@ -135,6 +135,8 @@ def run():
     design_index = 0
     while True:
 
+        print("Design #{}".format(design_index))
+
         num_inp = 0
         num_out = 0
         num_ino = 0
@@ -194,7 +196,7 @@ def run():
                     "output": used_sites[2:4],
                     "inout": used_sites[4:5],
                 })
-            print(region, iosettings)
+            print("", region, iosettings)
 
         # No more
         if len(region_data) == 0:
diff --git a/minitests/iostandard/syn+par.tcl b/minitests/iostandard/syn+par.tcl
index e75a63c8..363d760d 100644
--- a/minitests/iostandard/syn+par.tcl
+++ b/minitests/iostandard/syn+par.tcl
@@ -1,4 +1,4 @@
-create_project -force -name $env(PROJECT_NAME) -part $env(VIVADO_PART)
+create_project -force -name $env(PROJECT_NAME) -part $env(PART)
 
 set_property SEVERITY {Warning} [get_drc_checks NSTD-1]
 set_property SEVERITY {Warning} [get_drc_checks UCIO-1]