diff --git a/src/unisoc_unlock/cli.py b/src/unisoc_unlock/cli.py
index da6265e..5ef071a 100755
--- a/src/unisoc_unlock/cli.py
+++ b/src/unisoc_unlock/cli.py
@@ -8,6 +8,8 @@
 from Crypto.PublicKey import RSA
 import base64
 import io
+import argparse
+import importlib.metadata
 
 
 class OemIdToken:
@@ -25,48 +27,96 @@ def __call__(self, fb_msg):
         self.n += 1
 
 
-def sign_token(tok, key_file):
-    priv_key = RSA.importKey(open(key_file).read())
-    h = SHA256.new(tok)
-    signature = PKCS1_v1_5.new(priv_key).sign(h)
-    return signature
+class BootloaderCmd:
+    def sign_token(self, tok, key_file):
+        priv_key = RSA.importKey(open(key_file).read())
+        h = SHA256.new(tok)
+        signature = PKCS1_v1_5.new(priv_key).sign(h)
+        return signature
 
+    def prepare(self):
+        try:
+            self.dev = fastboot.FastbootCommands()
+            self.dev.ConnectDevice()
+        except usb_exceptions.DeviceNotFoundError as e:
+            print('No device found: {}'.format(e), file=sys.stderr)
+            sys.exit(1)
+        except usb_exceptions.CommonUsbError as e:
+            print('Could not connect to device: {}'.format(e), file=sys.stderr)
+            sys.exit(1)
 
-def main():
-    try:
-        dev = fastboot.FastbootCommands()
-        dev.ConnectDevice()
-    except usb_exceptions.DeviceNotFoundError as e:
-        print('No device found: {}'.format(e), file=sys.stderr)
-        sys.exit(1)
-    except usb_exceptions.CommonUsbError as e:
-        print('Could not connect to device: {}'.format(e), file=sys.stderr)
-        sys.exit(1)
+        oem_id = OemIdToken()
+        try:
+            self.dev.Oem('get_identifier_token', info_cb=oem_id)
+        except Exception as e:
+            print(f'Fastboot error: {str(e)}')
+            sys.exit(1)
 
-    oem_id = OemIdToken()
-    try:
-        dev.Oem('get_identifier_token', info_cb=oem_id)
-    except Exception as e:
-        print(f'Fastboot error: {str(e)}')
-        sys.exit(1)
+        print(f'OEM ID: {oem_id.id}')
+        id = oem_id.id.ljust(2*64, '0')
+        id_raw = base64.b16decode(id, casefold=True)
+        pemfile = os.path.join(
+            os.path.dirname(__file__),
+            'rsa4096_vbmeta.pem'
+        )
+        sgn = self.sign_token(id_raw, pemfile)
 
-    print(f'OEM ID: {oem_id.id}')
-    id = oem_id.id.ljust(2*64, '0')
-    id_raw = base64.b16decode(id, casefold=True)
-    pemfile = os.path.join(
-        os.path.dirname(__file__),
-        'rsa4096_vbmeta.pem'
-    )
-    sgn = sign_token(id_raw, pemfile)
+        print('Download signature')
+        self.dev.Download(io.BytesIO(sgn), source_len=len(sgn))
+
+
+class BootloaderUnlock(BootloaderCmd):
+    def __call__(self):
+        print('Preparing to unlock the bootloader')
+        self.prepare()
+
+        print('Unlock bootloader, pls follow instructions on device screen')
+        self.dev._SimpleCommand(
+            b'flashing unlock_bootloader', timeout_ms=60*1000)
 
-    print('Download signature')
-    dev.Download(io.BytesIO(sgn), source_len=len(sgn))
+        print('Bootloader unlocked.')
+        self.dev.Close()
 
-    print('Unlock bootloader, pls follow instructions on device screen')
-    dev._SimpleCommand(b'flashing unlock_bootloader', timeout_ms=60*1000)
 
-    print('Bootloader unlocked.')
-    dev.Close()
+class BootloaderLock(BootloaderCmd):
+    def __call__(self):
+        print('Preparing to lock the bootloader')
+        self.prepare()
+
+        print('Lock bootloader, pls follow instructions on device screen')
+        self.dev._SimpleCommand(
+            b'flashing lock_bootloader', timeout_ms=60*1000)
+
+        print('Bootloader locked.')
+        self.dev.Close()
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description='Lock/Unlock tool for Spreadtrum/Unisoc bootloader'
+    )
+    parser.add_argument('command',
+                        type=str,
+                        nargs='?',
+                        help='Command (lock|unlock), default=unlock'
+                        )
+    parser.add_argument('--version',
+                        action='version',
+                        version='%(prog)s ' +
+                        importlib.metadata.version('unisoc-unlock')
+                        )
+
+    args = parser.parse_args()
+
+    if args.command == 'lock':
+        cmd = BootloaderLock()
+    elif args.command in ['unlock', None]:
+        cmd = BootloaderUnlock()
+    else:
+        print(f'Unknown command {args.command}', file=sys.stderr)
+        sys.exit(1)
+
+    cmd()
 
 
 if __name__ == '__main__':