diff --git a/scripts/flash_can.py b/scripts/flash_can.py
index 08f9435..fdb162a 100755
--- a/scripts/flash_can.py
+++ b/scripts/flash_can.py
@@ -50,13 +50,7 @@ BOOTLOADER_CMDS = {
 }
 
 ACK_SUCCESS = 0xa0
-NACK_RESPONSES = {
-    0xf0: "Invalid Command",
-    0xf1: "CRC Mismatch",
-    0xf2: "Invalid Payload",
-    0xf3: "Invalid Trailer",
-    0xf4: "Invalid Payload Length"
-}
+NACK = 0xf1
 
 # Klipper Admin Defs (for jumping to bootloader)
 KLIPPER_ADMIN_ID = 0x3f0
@@ -87,20 +81,26 @@ class CanFlasher:
         self.file_size = 0
         self.block_size = 64
         self.block_count = 0
+        self.app_start_addr = 0
 
     async def connect_btl(self):
         output_line("Attempting to connect to bootloader")
         ret = await self.send_command('CONNECT')
-        self.block_size, = struct.unpack(">H", ret[2:])
+        ver_bytes, start_addr, self.block_size = struct.unpack("<4sII", ret)
+        self.app_start_addr = start_addr
+        proto_version = ".".join([str(v) for v in reversed(ver_bytes[:3])])
         if self.block_size not in [64, 128, 256, 512]:
             raise FlashCanError("Invalid Block Size: %d" % (self.block_size,))
-        output_line("Connected, Block Size: %d bytes" % (self.block_size,))
+        output_line(
+            f"CanBoot Connected\nProtocol Version: {proto_version}\n"
+            f"Block Size: {self.block_size} bytes\n"
+            f"Application Start: 0x{self.app_start_addr:4X}"
+        )
 
     async def send_command(
         self,
         cmdname: str,
         payload: bytes = b"",
-        response_length: int = 12,
         tries: int = 5
     ) -> bytearray:
         word_cnt = (len(payload) // 4) & 0xFF
@@ -110,31 +110,37 @@ class CanFlasher:
         out_cmd.append(word_cnt)
         if payload:
             out_cmd.extend(payload)
+        crc = crc16_ccitt(out_cmd[2:])
+        out_cmd.extend(struct.pack("<H", crc))
         out_cmd.extend(CMD_TRAILER)
-        crc = crc16_ccitt(out_cmd)
-        out_cmd.extend(struct.pack(">H", crc))
         while tries:
+            data = bytearray()
+            recd_len = 0
             try:
-                ret = await self.node.write_with_response(
-                    out_cmd, response_length
-                )
-                data = bytearray(ret)
+                self.node.write(out_cmd)
+                read_done = False
+                while not read_done:
+                    ret = await self.node.readuntil()
+                    data.extend(ret)
+                    while len(data) > 7:
+                        if data[:2] != CMD_HEADER:
+                            data = data[1:]
+                            continue
+                        recd_len = data[3] * 4
+                        read_done = len(data) == recd_len + 8
+                        break
+
             except Exception:
                 logging.exception("Can Read Error")
             else:
-                header = data[:2]
-                trailer = data[-4:-2]
-                recd_crc, = struct.unpack(">H", data[-2:])
-                calc_crc = crc16_ccitt(data[:-2])
+                trailer = data[-2:]
+                recd_crc, = struct.unpack("<H", data[-4:-2])
+                calc_crc = crc16_ccitt(data[2:-4])
                 recd_ack = data[2]
-                recd_len = data[3] * 4
-                cmd_response = data[4]
-                if header != CMD_HEADER:
-                    logging.info(
-                        f"Command '{cmdname}': Invalid Header Received "
-                        f"0x{header.hex()}"
-                    )
-                elif trailer != CMD_TRAILER:
+                cmd_response = 0
+                if recd_len:
+                    cmd_response, = struct.unpack("<I", data[4:8])
+                if trailer != CMD_TRAILER:
                     logging.info(
                         f"Command '{cmdname}': Invalid Trailer Received "
                         f"0x{trailer.hex()}"
@@ -145,26 +151,21 @@ class CanFlasher:
                         f"{calc_crc}, received {recd_crc}"
                     )
                 elif recd_ack != ACK_SUCCESS:
-                    nack_string = NACK_RESPONSES.get(recd_ack, "Unknown Error")
-                    msg = f"Command '{cmdname}': Received NACK, {nack_string}"
-                    if recd_ack == 0xf0:
-                        msg += f", 0x{cmd_response:2x}"
-                    elif recd_ack == 0xf1:
-                        mcu_crc, = struct.unpack(">H", data[6:8])
-                        msg += f", sent crc: {crc}, mcu_crc: {mcu_crc}"
-                    logging.info(msg)
+                    logging.info(f"Command '{cmdname}': Received NACK")
                 elif cmd_response != cmd:
                     logging.info(
                         f"Command '{cmdname}': Acknowledged wrong command, "
                         f"expected: {cmd:2x}, received: {cmd_response:2x}"
                     )
                 else:
-                    # Validation passed, return payload
-                    return data[4:recd_len + 4]
+                    # Validation passed, return payload sans command
+                    if recd_len <= 4:
+                        return bytearray()
+                    return data[8:recd_len + 4]
             tries -= 1
             # clear the read buffer
             try:
-                await self.node.read(256, timeout=.1)
+                await self.node.read(1024, timeout=.1)
             except asyncio.TimeoutError:
                 pass
             await asyncio.sleep(.1)
@@ -179,6 +180,7 @@ class CanFlasher:
             f.seek(0, os.SEEK_END)
             self.file_size = f.tell()
             f.seek(0)
+            flash_address = self.app_start_addr
             while True:
                 buf = f.read(self.block_size)
                 if not buf:
@@ -186,21 +188,22 @@ class CanFlasher:
                 if len(buf) < self.block_size:
                     buf += b"\xFF" * (self.block_size - len(buf))
                 self.fw_sha.update(buf)
-                prefix = struct.pack(">I", self.block_count)
+                prefix = struct.pack("<I", flash_address)
                 for _ in range(3):
                     resp = await self.send_command('SEND_BLOCK', prefix + buf)
-                    recd_block, = struct.unpack(">H", resp[2:])
-                    if recd_block == self.block_count:
+                    recd_addr, = struct.unpack("<I", resp)
+                    if recd_addr == flash_address:
                         break
                     logging.info(
-                        f"Block write mismatch: expected: {self.block_count}, "
-                        f"received: {recd_block}"
+                        f"Block write mismatch: expected: {flash_address:4X}, "
+                        f"received: {recd_addr:4X}"
                     )
                     await asyncio.sleep(.1)
                 else:
                     raise FlashCanError(
-                        f"Flash write failed, block {self.block_count}"
+                        f"Flash write failed, block address 0x{recd_addr:4X}"
                     )
+                flash_address += self.block_size
                 self.block_count += 1
                 uploaded = self.block_count * self.block_size
                 pct = int(uploaded / float(self.file_size) * 100 + .5)
@@ -208,7 +211,7 @@ class CanFlasher:
                     last_percent += 2.
                     output("#")
             resp = await self.send_command('SEND_EOF')
-            page_count, = struct.unpack(">H", resp[2:])
+            page_count, = struct.unpack("<I", resp)
             output_line("]\n\nWrite complete: %d pages" % (page_count))
 
     async def verify_file(self):
@@ -217,15 +220,16 @@ class CanFlasher:
         output("\n[")
         ver_sha = hashlib.sha1()
         for i in range(self.block_count):
+            flash_address = i * self.block_size + self.app_start_addr
             for _ in range(3):
-                payload = struct.pack(">I", i)
-                resp = await self.send_command("REQUEST_BLOCK", payload, 76)
-                recd_block, = struct.unpack(">H", resp[2:4])
-                if recd_block == i:
+                payload = struct.pack("<I", flash_address)
+                resp = await self.send_command("REQUEST_BLOCK", payload)
+                recd_addr, = struct.unpack("<I", resp[:4])
+                if recd_addr == flash_address:
                     break
                 logging.info(
-                    f"Block read mismatch: expected: {i}, "
-                    f"received: {recd_block}"
+                    f"Block read mismatch: expected: 0x{flash_address:4X}, "
+                    f"received: 0x{recd_addr}"
                 )
                 await asyncio.sleep(.1)
             else:
@@ -263,6 +267,11 @@ class CanNode:
     ) -> bytes:
         return await asyncio.wait_for(self._reader.readexactly(n), timeout)
 
+    async def readuntil(
+        self, sep: bytes = b"\x03", timeout: Optional[float] = 2
+    ) -> bytes:
+        return await asyncio.wait_for(self._reader.readuntil(sep), timeout)
+
     def write(self, payload: Union[bytes, bytearray]) -> None:
         if isinstance(payload, bytearray):
             payload = bytes(payload)
@@ -491,8 +500,14 @@ def main():
         "-q", "--query", action="store_true",
         help="Query Bootloader Device IDs"
     )
+    parser.add_argument(
+        "-v", "--verbose", action="store_true",
+        help="Enable verbose responses"
+    )
 
     args = parser.parse_args()
+    if not args.verbose:
+        logging.getLogger().setLevel(logging.CRITICAL)
     intf = args.interface
     fpath = pathlib.Path(args.firmware).expanduser().resolve()
     loop = asyncio.get_event_loop()