fix(autodetection): Remove the Unsupported detection protocol stage

docs/en/espefuse/dump-cmd.rst

@@ -34,8 +34,7 @@ The order of registers in the dump:
 
         > espefuse.py  dump
 
-        Detecting chip type... Unsupported detection protocol, switching and trying again...
-        Connecting....
+        Connecting.........
         Detecting chip type... ESP32
         BLOCK0          (                ) [0 ] read_regs: 00000000 7e5a6e58 00e294b9 0000a200 00000333 00100000 00000004
         BLOCK1          (flash_encryption) [1 ] read_regs: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

docs/en/espefuse/summary-cmd.rst

@@ -109,8 +109,6 @@ Save Json Format Summary To File
 
     > espefuse.py summary --format json --file efuses.json
 
-    Connecting..........
-    Detecting chip type... Unsupported detection protocol, switching and trying again...
     Connecting....
     Detecting chip type... ESP32
 

esptool/cmds.py

@@ -128,7 +128,7 @@ def detect_chip(
     This way we use one memory read and compare it to the magic number for each chip.
     """
     try:
-        log.print("Detecting chip type...", end="")
+        log.print("Detecting chip type...", end="", flush=True)
         chip_id = detect_port.get_chip_id()
         for cls in ROM_LIST:
             # cmd not supported on ESP8266 and ESP32 + ESP32-S2 doesn't return chip-id
@@ -147,39 +147,41 @@ def detect_chip(
                 break
         else:
             err_msg = f"Unexpected chip ID value {chip_id}."
-    except (UnsupportedCommandError, struct.error, FatalError) as e:
+    except (UnsupportedCommandError, struct.error, FatalError):
         # UnsupportedCommandError: ESP8266/ESP32 ROM
         # struct.error: ESP32-S2
         # FatalError: ESP8266/ESP32 STUB
-        log.print(" Unsupported detection protocol, switching and trying again...")
         try:
-            # ESP32/ESP8266 are reset after an unsupported command, need to reconnect
-            # (not needed on ESP32-S2)
-            if not isinstance(e, struct.error):
-                detect_port.connect(
-                    connect_mode, connect_attempts, detecting=True, warnings=False
-                )
-            log.print("Detecting chip type...", end="", flush=True)
             chip_magic_value = detect_port.read_reg(
                 ESPLoader.CHIP_DETECT_MAGIC_REG_ADDR
             )
-
-            for cls in ROM_LIST:
-                if not cls.USES_MAGIC_VALUE:
-                    continue
-                if chip_magic_value == cls.MAGIC_VALUE:
-                    inst = cls(detect_port._port, baud, trace_enabled=trace_enabled)
-                    inst = check_if_stub(inst)
-                    inst._post_connect()
-                    break
-            else:
-                err_msg = f"Unexpected chip magic value {chip_magic_value:#010x}."
         except UnsupportedCommandError:
             raise FatalError(
                 "Unsupported Command Error received. "
                 "Probably this means Secure Download Mode is enabled, "
                 "autodetection will not work. Need to manually specify the chip."
             )
+        except FatalError:
+            log.print(" Autodetection failed, trying again...")
+            detect_port.connect(
+                connect_mode, connect_attempts, detecting=True, warnings=False
+            )
+            log.print("Detecting chip type...", end="", flush=True)
+            chip_magic_value = detect_port.read_reg(
+                ESPLoader.CHIP_DETECT_MAGIC_REG_ADDR
+            )
+
+        for cls in ROM_LIST:
+            if not cls.USES_MAGIC_VALUE:
+                continue
+            if chip_magic_value == cls.MAGIC_VALUE:
+                inst = cls(detect_port._port, baud, trace_enabled=trace_enabled)
+                inst = check_if_stub(inst)
+                inst._post_connect()
+                break
+        else:
+            err_msg = f"Unexpected chip magic value {chip_magic_value:#010x}."
+
     if inst is not None:
         return inst
 

esptool/loader.py

@@ -509,7 +509,8 @@ class ESPLoader(object):
                 if byte(data, 0) != 0 and byte(data, 1) == self.ROM_INVALID_RECV_MSG:
                     # Unsupported read_reg can result in
                     # more than one error response for some reason
-                    self.flush_input()
+                    time.sleep(0.2)  # Wait for input buffer to fill
+                    self.flush_input()  # Flush input buffer of hanging response
                     raise UnsupportedCommandError(self, op)
 
         finally:

test/test_esptool.py

@@ -1379,8 +1379,6 @@ class TestBootloaderHeaderRewriteCases(EsptoolTestCase):
 class TestAutoDetect(EsptoolTestCase):
     def _check_output(self, output):
         expected_chip_name = esptool.util.expand_chip_name(arg_chip)
-        if arg_chip not in ["esp8266", "esp32", "esp32s2"]:
-            assert "Unsupported detection protocol" not in output
         assert f"Detecting chip type... {expected_chip_name}" in output
         assert f"{'Chip type:':<20}{expected_chip_name}" in output
 

test/test_esptool_sdm.py

@@ -31,9 +31,8 @@ class TestSecureDownloadMode(EsptoolTestCase):
 
         if arg_chip == "esp32s2":  # no autodetection from security info, only magic no.
             assert "Secure Download Mode is enabled" in output
-            assert "Unsupported detection protocol" in output
+            assert "autodetection will not work" in output
         else:
-            assert "Unsupported detection protocol" not in output
             assert f"Detecting chip type... {self.expected_chip_name}" in output
             assert (
                 f"{'Chip type:':<20}{self.expected_chip_name} "