diff --git a/pynitrokey/cli/start.py b/pynitrokey/cli/start.py
index 6eb0f39d..7a3abb48 100644
--- a/pynitrokey/cli/start.py
+++ b/pynitrokey/cli/start.py
@@ -17,7 +17,7 @@
 from pynitrokey.start.usb_strings import get_devices as get_devices_strings
 
 from pynitrokey.start.upgrade_by_passwd import validate_gnuk, validate_regnual, logger, \
-    start_update, DEFAULT_WAIT_FOR_REENUMERATION, DEFAULT_PW3, IS_LINUX
+    start_update, DEFAULT_WAIT_FOR_REENUMERATION, DEFAULT_PW3, IS_LINUX, show_kdf_details
 from pynitrokey.start.threaded_log import ThreadLog
 
 from usb.core import USBError
@@ -112,9 +112,18 @@ def update(regnual, gnuk, default_password, password, wait_e, keyno, verbose, ye
         start_update(*args)
 
 
+@click.command()
+@click.option(
+    '--passwd', default='', help='password'
+)
+def kdf_details(passwd):
+    return show_kdf_details(passwd)
+
+
 start.add_command(list)
 start.add_command(set_identity)
 start.add_command(update)
+start.add_command(kdf_details)
 # start.add_command(rng)
 # start.add_command(reboot)
 # rng.add_command(hexbytes)
diff --git a/pynitrokey/start/gnuk_token.py b/pynitrokey/start/gnuk_token.py
index bea66283..b92643da 100644
--- a/pynitrokey/start/gnuk_token.py
+++ b/pynitrokey/start/gnuk_token.py
@@ -27,6 +27,8 @@
 from array import array
 
 # Possible Gnuk Token products
+from pynitrokey.start.usb_strings import get_dict_for_device
+
 USB_PRODUCT_LIST=[
     { 'vendor' : 0x234b, 'product' : 0x0000 }, # FSIJ Gnuk Token
     { 'vendor' : 0x20a0, 'product' : 0x4211 }, # Nitrokey Start
@@ -661,9 +663,11 @@ def get_gnuk_device(verbose=True, logger: logging.Logger=None):
             if logger:
                 logger.debug('{} {} {}'.format(dev.filename, config.value, intf.interfaceNumber))
             if verbose:
-                print("Device: %s" % dev.filename)
-                print("Configuration: %d" % config.value)
-                print("Interface: %d" % intf.interfaceNumber)
+                try:
+                    d = get_dict_for_device(dev)
+                    print(f'Device: {d["Product"]} {d["Serial"]}')
+                except:
+                    print(f'Device: name: "{dev.filename}", c/i: {config.value}/{intf.interfaceNumber}')
             break
         except:
             pass
diff --git a/pynitrokey/start/upgrade_by_passwd.py b/pynitrokey/start/upgrade_by_passwd.py
index 4b4f74cf..4c978568 100755
--- a/pynitrokey/start/upgrade_by_passwd.py
+++ b/pynitrokey/start/upgrade_by_passwd.py
@@ -25,6 +25,7 @@
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 import tempfile
+from pprint import pprint
 
 IMPORT_ERROR_HELP = """
 Some required modules are missing from this environment.
@@ -352,6 +353,53 @@ def download_file_or_exit(url):
     return firmware_data
 
 
+def show_kdf_details(passwd):
+    gnuk = None
+    try:
+        gnuk = get_gnuk_device(logger=logger, verbose=True)
+    except ValueError as e:
+        if 'No ICC present' in str(e):
+            print('Cannot connect to device. Closing other open connections.')
+            kill_smartcard_services()
+            return
+        else:
+            raise
+    gnuk.cmd_select_openpgp()
+    # Compute passwd data
+    try:
+        kdf_data = gnuk.cmd_get_data(0x00, 0xf9).tobytes()
+    except:
+        kdf_data = b""
+    if kdf_data == b"":
+        print('KDF not set')
+        # passwd_data = passwd.encode('UTF-8')
+    else:
+        algo, subalgo, iters, salt_user, salt_reset, salt_admin, \
+        hash_user, hash_admin = parse_kdf_data(kdf_data)
+        if salt_admin:
+            salt = salt_admin
+        else:
+            salt = salt_user
+        d = {
+            'algo': algo,
+            'subalgo': subalgo,
+            'iters': iters,
+            'salt_user': binascii.b2a_hex(salt_user),
+            'salt_reset': binascii.b2a_hex(salt_reset),
+            'salt_admin': binascii.b2a_hex(salt_admin),
+            'hash_user': binascii.b2a_hex(hash_user),
+            'hash_admin': binascii.b2a_hex(hash_admin),
+        }
+        pprint(d, width=100)
+        if passwd:
+            try:
+                passwd_data = kdf_calc(passwd, salt, iters)
+                print(f'passwd_data: {binascii.b2a_hex(passwd_data)}')
+            except ValueError as e:
+                print(str(e))
+        else:
+            print('Provide password to calculate final hash')
+
 def start_update(regnual, gnuk, default_password, password, wait_e, keyno, verbose, yes,
         skip_bootloader, green_led):