diff --git a/templates/f7/flash.jlink b/templates/f7/flash.jlink
deleted file mode 100644
index 34f514d..0000000
--- a/templates/f7/flash.jlink
+++ /dev/null
@@ -1,7 +0,0 @@
-if SWD
-speed 4000
-device STM32F746ZG
-loadbin build/f7.bin 0x8000000
-r
-g
-exit
diff --git a/templates/f7/ram_pattern.bin b/templates/f7/ram_pattern.bin
new file mode 100644
index 0000000..0afb316
Binary files /dev/null and b/templates/f7/ram_pattern.bin differ
diff --git a/templates/f7/test b/templates/f7/test
index 6c58892..27cada9 100755
--- a/templates/f7/test
+++ b/templates/f7/test
@@ -8,17 +8,52 @@ import serial
 import subprocess
 
 
+RAM_SIZE = 0x50000
 
 def eprint(*args, **kargs):
     print(*args, file=sys.stderr, **kargs)
 
 
-def flash():
+def popen_jlink():
     pipe = subprocess.PIPE
-    cmd = ['JLinkExe', 'flash.jlink']
-    p = subprocess.Popen(cmd,
-            stdout=sys.stderr, stdin=pipe)
-    stdout, stderr = p.communicate("") 
+    cmd = ['JLinkExe']
+    cmd.extend(['-autoconnect', '1'])
+    cmd.extend(['-device', 'STM32F746ZG'])
+    cmd.extend(['-if', 'swd'])
+    cmd.extend(['-speed', '4000'])
+    return subprocess.Popen(cmd, stdout=sys.stderr, stdin=pipe)
+
+
+def flash():
+    p = popen_jlink()
+    return p.communicate(("""
+loadbin build/f7.bin 0x8000000
+r
+g
+exit
+    """).encode('ascii'))
+
+
+def fill_ram():
+    p = popen_jlink()
+    return p.communicate(("""
+h
+loadbin ram_pattern.bin 0x20000000
+savebin ram_copy.bin 0x20000000 0x%x
+r
+g
+exit
+    """ % RAM_SIZE).encode('ascii'))
+
+
+def dump_ram():
+    p = popen_jlink()
+    return p.communicate(("""
+h
+savebin ram_dump.bin 0x20000000 0x%x
+exit
+    """ % RAM_SIZE).encode('ascii'))
+
 
 def get_serial():
     import serial.tools.list_ports
@@ -113,16 +148,10 @@ def main(argv):
     uartp = UARTP(ser)
 
     flash()
+    fill_ram()
     eprint("Flashed")
     time.sleep(0.1)
 
-    ser.setDTR(False)  # IO0=HIGH
-    ser.setRTS(True)   # EN=LOW, chip in reset
-    time.sleep(0.1)
-    ser.setDTR(False)  # IO0=HIGH
-    ser.setRTS(False)  # EN=HIGH, chip out of reset
-    time.sleep(1)
-
     def stdin_read(n):
         b = sys.stdin.buffer.read(n)
         if len(b) != n:
@@ -176,6 +205,37 @@ def main(argv):
                 raise Exception("Unacknowledged variable transfer")
             eprint("Operation %c completed successfully" % action)
 
+        elif action in b"u":
+            dump_ram()
+            with open("ram_copy.bin", 'rb') as dump:
+                dump_a = dump.read()
+            with open("ram_dump.bin", 'rb') as dump:
+                dump_b = dump.read()
+            
+            if len(dump_a) != RAM_SIZE or len(dump_b) != RAM_SIZE:
+                raise Exception("Wrong dump sizes: 0x%x, 0x%x" % (len(dump_a), len(dump_b)))
+           
+            streaks = []
+            streak_beg = 0
+            streak_end = 0
+            for i in range(len(dump_a)):
+                if dump_a[i] == dump_b[i]:
+                    streak_end = i
+                else:
+                    if streak_end != streak_beg:
+                        streaks.append((streak_beg, streak_end))
+                    streak_beg = i
+                    streak_end = i
+
+            for b, e in streaks:
+                eprint("equal bytes from 0x%x to 0x%x (length: %d)" % (b, e, e-b))
+
+            b, e = max(streaks, key=lambda a: a[1]-a[0])
+            eprint("longest equal bytes streak from 0x%x to 0x%x (length: %d)" % (b, e, e-b))
+            v = struct.pack("<II", 4, e-b)
+            sys.stdout.buffer.write(v)
+            sys.stdout.flush()
+
         else:
             raise Exception("Unknown action %c" % action)
         
diff --git a/test.py b/test.py
index 07bd135..5de8fee 100755
--- a/test.py
+++ b/test.py
@@ -6,6 +6,8 @@ import sys
 import struct
 from subprocess import Popen, PIPE
 
+MEASURE_TIME = True
+MEASURE_RAM = False
 
 def main(argv):
     if len(argv) < 3:
@@ -16,11 +18,13 @@ def main(argv):
     for attempt in range(3):
         print("beginning test %d of '%s' using test vectors '%s'" % (attempt, ' '.join(cmd), argv[1]))
         try:
-            measurements = begin_measurement()
+            if MEASURE_TIME:
+                measurements = begin_measurement()
             try:
                 test(argv[1], cmd)
             finally:
-                end_measurement(measurements)
+                if MEASURE_TIME:
+                    end_measurement(measurements)
             print("TEST SUCCESSFUL")
             return 0
 
@@ -114,6 +118,12 @@ def test(test_file, cmd):
             print("   m = %s" % output.hex())
             if m != output:
                 raise Exception("output of encryption is different from expected ciphertext")
+            
+            if MEASURE_RAM:
+                write(b'u')
+                output = obtain()
+                print("  untouched memory = %d" % struct.unpack("<I", output))
+                break
 
         elif res is not None:
             if res[1].lower() == 'count':