Add support for write unprotection

README.md

@@ -187,7 +187,7 @@ adapter (it needs to toggle, whereas `BOOT0` does not).
 
 ## Not currently supported
 
-* Command-line argument for write protection/unprotection.
+* Command-line argument for write protection.
 * STM8 devices (ST `UM0560`).
 * Other bootloader protocols (e.g. I2C, HEX -> implemented in `stm32flash`).
 

src/stm32loader/args.py

@@ -83,6 +83,10 @@ def parse_arguments(arguments):
         "-x", "--protect", action="store_true", help="Protect flash against readout."
     )
 
+    parser.add_argument(
+        "--write-unprotect", action="store_true", help="Disable write protection before flashing"
+    )
+
     parser.add_argument("-w", "--write", action="store_true", help="Write file content to flash.")
 
     parser.add_argument(

src/stm32loader/bootloader.py

@@ -772,8 +772,12 @@ def write_protect(self, pages):
 
     def write_unprotect(self):
         """Disable write protection of the flash memory."""
+        self.debug(10, "Disabling write protection")
         self.command(self.Command.WRITE_UNPROTECT, "Write unprotect")
         self._wait_for_ack("0x73 write unprotect failed")
+
+        time.sleep(0.1)
+        self.reset_from_system_memory()
         self.debug(10, "    Write Unprotect done")
 
     def readout_protect(self):

src/stm32loader/emulated/fake.py

@@ -61,6 +61,10 @@ def receive(self):
             command_bytes = yield
             command_value = struct.unpack("B", command_bytes)[0]
 
+            # No CRC is sent for SYNCHRONIZE
+            if command_value == self.Command.SYNCHRONIZE:
+                continue
+
             # Receive CRC byte.
             yield
             self.ack()
@@ -112,8 +116,12 @@ def receive(self):
                 # Record data in flash memory.
                 flash_offset = address - 0x_0800_0000
                 self.flash_memory[flash_offset : flash_offset + byte_count] = data
+
+            elif command_value == self.Command.WRITE_UNPROTECT.value:
+                pass
+
             else:
-                raise NotImplementedError()
+                raise NotImplementedError(hex(command_value))
 
     def write(self, data):
         # Send to coroutine.
@@ -132,11 +140,12 @@ def read(self, length=1):  # pylint: disable=unused-argument
 class FakeConfiguration:
     """Represent a configuration for test purposes."""
 
-    def __init__(self, erase, write, verify, firmware_file, family=None):
+    def __init__(self, erase, write, verify, write_unprotect, firmware_file, family=None):
         self.erase = erase
         self.write = write
         self.verify = verify
         self.data_file = firmware_file
+        self.write_unprotect = write_unprotect
         self.unprotect = False
         self.protect = False
         self.length = None

src/stm32loader/main.py

@@ -141,6 +141,16 @@ def perform_commands(self):
                 self.debug(0, "Quit")
                 self.stm32.reset_from_flash()
                 sys.exit(1)
+
+        if self.configuration.write_unprotect:
+            try:
+                self.stm32.write_unprotect()
+            except bootloader.CommandError:
+                self.debug(0, "Flash write unprotect failed")
+                self.debug(0, "Quit")
+                self.stm32.reset_from_flash()
+                sys.exit(1)
+
         if self.configuration.erase:
             try:
                 if self.configuration.length is None:

tests/integration/test_full_cycle.py

@@ -10,7 +10,12 @@
 def test_erase_write_verify_passes():
     loader = Stm32Loader()
     loader.configuration = FakeConfiguration(
-        erase=True, write=True, verify=True, firmware_file=FIRMWARE_FILE, family=None
+        erase=True,
+        write=True,
+        verify=True,
+        write_unprotect=True,
+        firmware_file=FIRMWARE_FILE,
+        family=None,
     )
     loader.connection = FakeConnection()
     loader.stm32 = Stm32Bootloader(loader.connection, device_family="F1", verbosity=5)

tests/unit/test_arguments.py

@@ -43,3 +43,7 @@ def test_parse_arguments_erase_without_port_complains_about_missing_argument(pro
         pytest.skip("Not sure why nothing is captured in some pytest runs?")
     assert "arguments are required: -p/--port" in error_output
     assert "STM32LOADER_SERIAL_PORT" in error_output
+
+
+def test_parse_arguments_write_unprotect(program):
+    program.parse_arguments(["--write-unprotect"])

tests/unit/test_bootloader.py

@@ -205,6 +205,14 @@ def test_write_protect_sends_page_addresses_and_checksum(bootloader, write):
     assert write.data_was_written(b"\x01\x08\x08")
 
 
+def test_write_unprotect_sends_command(bootloader, write):
+    bootloader.write_unprotect()
+    assert write.data_was_written(b"\x73"), write.written_data
+    assert write.data_was_written(bytearray([Stm32Bootloader.Command.SYNCHRONIZE])), (
+        write.written_data
+    )
+
+
 def test_verify_data_with_identical_data_passes():
     Stm32Bootloader.verify_data(b"\x05", b"\x05")