diff --git a/selfdrive/debug/internal/core_voltage_sweep.py b/selfdrive/debug/internal/core_voltage_sweep.py
index 5d7f85634b..c7c609560d 100755
--- a/selfdrive/debug/internal/core_voltage_sweep.py
+++ b/selfdrive/debug/internal/core_voltage_sweep.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 import os
+import sys
 import time
 
 print("starting at")
@@ -9,9 +10,14 @@ print("volts")
 os.system("echo 99e8000.cpr3-ctrl > /sys/devices/soc/spm-regulator-10/regulator/regulator.56/99e8000.cpr3-ctrl-vdd/driver/unbind")
 os.system("echo 1 > /sys/kernel/debug/regulator/pm8994_s11/enable")
 
-for i in range(900000, 465000, -10000):
-  print("setting voltage to",i)
+if len(sys.argv) > 1:
+  i = int(sys.argv[1])
   os.system("echo %d %d > /sys/kernel/debug/regulator/pm8994_s11/voltage" % (i,i))
-  time.sleep(1)
   os.system("cat /sys/kernel/debug/regulator/pm8994_s11/voltage")
+else:
+  for i in range(900000, 465000, -10000):
+    print("setting voltage to",i)
+    os.system("echo %d %d > /sys/kernel/debug/regulator/pm8994_s11/voltage" % (i,i))
+    os.system("cat /sys/kernel/debug/regulator/pm8994_s11/voltage")
+    time.sleep(1)