diff --git a/lerobot/common/robot_devices/cameras/intelrealsense.py b/lerobot/common/robot_devices/cameras/intelrealsense.py
index 29e99ea3c..945de837d 100644
--- a/lerobot/common/robot_devices/cameras/intelrealsense.py
+++ b/lerobot/common/robot_devices/cameras/intelrealsense.py
@@ -77,9 +77,9 @@ def save_image(img_array, serial_number, frame_index, images_dir):
         path = images_dir / f"camera_{serial_number}_frame_{frame_index:06d}.png"
         path.parent.mkdir(parents=True, exist_ok=True)
         img.save(str(path), quality=100)
-        logging.info(f"Saved image: {path}")
+        logging.info("Saved image: %s", path)
     except Exception as e:
-        logging.error(f"Failed to save image for camera {serial_number} frame {frame_index}: {e}")
+        logging.error("Failed to save image for camera %s frame %s: %s", serial_number, frame_index, e)
 
 
 def save_images_from_cameras(
@@ -447,7 +447,7 @@ class IntelRealSenseCamera:
             num_tries += 1
             time.sleep(1 / self.fps)
             if num_tries > self.fps and (self.thread.ident is None or not self.thread.is_alive()):
-                raise Exception(
+                raise TimeoutError(
                     "The thread responsible for `self.async_read()` took too much time to start. There might be an issue. Verify that `self.thread.start()` has been called."
                 )
 
diff --git a/lerobot/common/robot_devices/cameras/opencv.py b/lerobot/common/robot_devices/cameras/opencv.py
index d15a48f6b..42164853c 100644
--- a/lerobot/common/robot_devices/cameras/opencv.py
+++ b/lerobot/common/robot_devices/cameras/opencv.py
@@ -45,7 +45,7 @@ from lerobot.common.utils.utils import capture_timestamp_utc
 MAX_OPENCV_INDEX = 60
 
 
-def find_cameras(raise_when_empty=False, max_index_search_range=MAX_OPENCV_INDEX, mock=False) -> list[dict]:
+def find_cameras(max_index_search_range=MAX_OPENCV_INDEX, mock=False) -> list[dict]:
     cameras = []
     if platform.system() == "Linux":
         print("Linux detected. Finding available camera indices through scanning '/dev/video*' ports")
diff --git a/lerobot/common/robot_devices/motors/dynamixel.py b/lerobot/common/robot_devices/motors/dynamixel.py
index 186f7124c..eac9cb19d 100644
--- a/lerobot/common/robot_devices/motors/dynamixel.py
+++ b/lerobot/common/robot_devices/motors/dynamixel.py
@@ -169,7 +169,8 @@ def convert_degrees_to_steps(degrees: float | np.ndarray, models: str | list[str
     return steps
 
 
-def convert_to_bytes(value, bytes, mock=False):
+# TODO(Steven): Similar function in feetch.py, should be moved to a common place.
+def convert_to_bytes(value, byte, mock=False):
     if mock:
         return value
 
@@ -177,16 +178,16 @@ def convert_to_bytes(value, bytes, mock=False):
 
     # Note: No need to convert back into unsigned int, since this byte preprocessing
     # already handles it for us.
-    if bytes == 1:
+    if byte == 1:
         data = [
             dxl.DXL_LOBYTE(dxl.DXL_LOWORD(value)),
         ]
-    elif bytes == 2:
+    elif byte == 2:
         data = [
             dxl.DXL_LOBYTE(dxl.DXL_LOWORD(value)),
             dxl.DXL_HIBYTE(dxl.DXL_LOWORD(value)),
         ]
-    elif bytes == 4:
+    elif byte == 4:
         data = [
             dxl.DXL_LOBYTE(dxl.DXL_LOWORD(value)),
             dxl.DXL_HIBYTE(dxl.DXL_LOWORD(value)),
@@ -196,7 +197,7 @@ def convert_to_bytes(value, bytes, mock=False):
     else:
         raise NotImplementedError(
             f"Value of the number of bytes to be sent is expected to be in [1, 2, 4], but "
-            f"{bytes} is provided instead."
+            f"{byte} is provided instead."
         )
     return data
 
@@ -228,9 +229,9 @@ def assert_same_address(model_ctrl_table, motor_models, data_name):
     all_addr = []
     all_bytes = []
     for model in motor_models:
-        addr, bytes = model_ctrl_table[model][data_name]
+        addr, byte = model_ctrl_table[model][data_name]
         all_addr.append(addr)
-        all_bytes.append(bytes)
+        all_bytes.append(byte)
 
     if len(set(all_addr)) != 1:
         raise NotImplementedError(
@@ -576,6 +577,8 @@ class DynamixelMotorsBus:
                 # (start_pos - values[i]) / resolution <= factor <= (end_pos - values[i]) / resolution
                 low_factor = (start_pos - values[i]) / resolution
                 upp_factor = (end_pos - values[i]) / resolution
+            else:
+                raise ValueError(f"Unknown calibration mode '{calib_mode}'.")
 
             if not in_range:
                 # Get first integer between the two bounds
@@ -596,10 +599,15 @@ class DynamixelMotorsBus:
                 elif CalibrationMode[calib_mode] == CalibrationMode.LINEAR:
                     out_of_range_str = f"{LOWER_BOUND_LINEAR} < {calib_val} < {UPPER_BOUND_LINEAR} %"
                     in_range_str = f"{LOWER_BOUND_LINEAR} < {calib_val} < {UPPER_BOUND_LINEAR} %"
+                else:
+                    raise ValueError(f"Unknown calibration mode '{calib_mode}'.")
 
                 logging.warning(
-                    f"Auto-correct calibration of motor '{name}' by shifting value by {abs(factor)} full turns, "
-                    f"from '{out_of_range_str}' to '{in_range_str}'."
+                    "Auto-correct calibration of motor '%s' by shifting value by {abs(factor)} full turns, "
+                    "from '%s' to '%s'.",
+                    name,
+                    out_of_range_str,
+                    in_range_str,
                 )
 
                 # A full turn corresponds to 360 degrees but also to 4096 steps for a motor resolution of 4096.
@@ -656,8 +664,8 @@ class DynamixelMotorsBus:
             motor_ids = [motor_ids]
 
         assert_same_address(self.model_ctrl_table, self.motor_models, data_name)
-        addr, bytes = self.model_ctrl_table[motor_models[0]][data_name]
-        group = dxl.GroupSyncRead(self.port_handler, self.packet_handler, addr, bytes)
+        addr, byte = self.model_ctrl_table[motor_models[0]][data_name]
+        group = dxl.GroupSyncRead(self.port_handler, self.packet_handler, addr, byte)
         for idx in motor_ids:
             group.addParam(idx)
 
@@ -674,7 +682,7 @@ class DynamixelMotorsBus:
 
         values = []
         for idx in motor_ids:
-            value = group.getData(idx, addr, bytes)
+            value = group.getData(idx, addr, byte)
             values.append(value)
 
         if return_list:
@@ -709,13 +717,13 @@ class DynamixelMotorsBus:
             models.append(model)
 
         assert_same_address(self.model_ctrl_table, models, data_name)
-        addr, bytes = self.model_ctrl_table[model][data_name]
+        addr, byte = self.model_ctrl_table[model][data_name]
         group_key = get_group_sync_key(data_name, motor_names)
 
         if data_name not in self.group_readers:
             # create new group reader
             self.group_readers[group_key] = dxl.GroupSyncRead(
-                self.port_handler, self.packet_handler, addr, bytes
+                self.port_handler, self.packet_handler, addr, byte
             )
             for idx in motor_ids:
                 self.group_readers[group_key].addParam(idx)
@@ -733,7 +741,7 @@ class DynamixelMotorsBus:
 
         values = []
         for idx in motor_ids:
-            value = self.group_readers[group_key].getData(idx, addr, bytes)
+            value = self.group_readers[group_key].getData(idx, addr, byte)
             values.append(value)
 
         values = np.array(values)
@@ -767,10 +775,10 @@ class DynamixelMotorsBus:
             values = [values]
 
         assert_same_address(self.model_ctrl_table, motor_models, data_name)
-        addr, bytes = self.model_ctrl_table[motor_models[0]][data_name]
-        group = dxl.GroupSyncWrite(self.port_handler, self.packet_handler, addr, bytes)
+        addr, byte = self.model_ctrl_table[motor_models[0]][data_name]
+        group = dxl.GroupSyncWrite(self.port_handler, self.packet_handler, addr, byte)
         for idx, value in zip(motor_ids, values, strict=True):
-            data = convert_to_bytes(value, bytes, self.mock)
+            data = convert_to_bytes(value, byte, self.mock)
             group.addParam(idx, data)
 
         for _ in range(num_retry):
@@ -821,17 +829,17 @@ class DynamixelMotorsBus:
         values = values.tolist()
 
         assert_same_address(self.model_ctrl_table, models, data_name)
-        addr, bytes = self.model_ctrl_table[model][data_name]
+        addr, byte = self.model_ctrl_table[model][data_name]
         group_key = get_group_sync_key(data_name, motor_names)
 
         init_group = data_name not in self.group_readers
         if init_group:
             self.group_writers[group_key] = dxl.GroupSyncWrite(
-                self.port_handler, self.packet_handler, addr, bytes
+                self.port_handler, self.packet_handler, addr, byte
             )
 
         for idx, value in zip(motor_ids, values, strict=True):
-            data = convert_to_bytes(value, bytes, self.mock)
+            data = convert_to_bytes(value, byte, self.mock)
             if init_group:
                 self.group_writers[group_key].addParam(idx, data)
             else:
diff --git a/lerobot/common/robot_devices/motors/feetech.py b/lerobot/common/robot_devices/motors/feetech.py
index 7d0d2a005..c3f053c20 100644
--- a/lerobot/common/robot_devices/motors/feetech.py
+++ b/lerobot/common/robot_devices/motors/feetech.py
@@ -148,7 +148,7 @@ def convert_degrees_to_steps(degrees: float | np.ndarray, models: str | list[str
     return steps
 
 
-def convert_to_bytes(value, bytes, mock=False):
+def convert_to_bytes(value, byte, mock=False):
     if mock:
         return value
 
@@ -156,16 +156,16 @@ def convert_to_bytes(value, bytes, mock=False):
 
     # Note: No need to convert back into unsigned int, since this byte preprocessing
     # already handles it for us.
-    if bytes == 1:
+    if byte == 1:
         data = [
             scs.SCS_LOBYTE(scs.SCS_LOWORD(value)),
         ]
-    elif bytes == 2:
+    elif byte == 2:
         data = [
             scs.SCS_LOBYTE(scs.SCS_LOWORD(value)),
             scs.SCS_HIBYTE(scs.SCS_LOWORD(value)),
         ]
-    elif bytes == 4:
+    elif byte == 4:
         data = [
             scs.SCS_LOBYTE(scs.SCS_LOWORD(value)),
             scs.SCS_HIBYTE(scs.SCS_LOWORD(value)),
@@ -175,7 +175,7 @@ def convert_to_bytes(value, bytes, mock=False):
     else:
         raise NotImplementedError(
             f"Value of the number of bytes to be sent is expected to be in [1, 2, 4], but "
-            f"{bytes} is provided instead."
+            f"{byte} is provided instead."
         )
     return data
 
@@ -207,9 +207,9 @@ def assert_same_address(model_ctrl_table, motor_models, data_name):
     all_addr = []
     all_bytes = []
     for model in motor_models:
-        addr, bytes = model_ctrl_table[model][data_name]
+        addr, byte = model_ctrl_table[model][data_name]
         all_addr.append(addr)
-        all_bytes.append(bytes)
+        all_bytes.append(byte)
 
     if len(set(all_addr)) != 1:
         raise NotImplementedError(
@@ -557,6 +557,8 @@ class FeetechMotorsBus:
                 # (start_pos - values[i]) / resolution <= factor <= (end_pos - values[i]) / resolution
                 low_factor = (start_pos - values[i]) / resolution
                 upp_factor = (end_pos - values[i]) / resolution
+            else:
+                raise ValueError(f"Unknown calibration mode {calib_mode}")
 
             if not in_range:
                 # Get first integer between the two bounds
@@ -577,10 +579,16 @@ class FeetechMotorsBus:
                 elif CalibrationMode[calib_mode] == CalibrationMode.LINEAR:
                     out_of_range_str = f"{LOWER_BOUND_LINEAR} < {calib_val} < {UPPER_BOUND_LINEAR} %"
                     in_range_str = f"{LOWER_BOUND_LINEAR} < {calib_val} < {UPPER_BOUND_LINEAR} %"
+                else:
+                    raise ValueError(f"Unknown calibration mode {calib_mode}")
 
                 logging.warning(
-                    f"Auto-correct calibration of motor '{name}' by shifting value by {abs(factor)} full turns, "
-                    f"from '{out_of_range_str}' to '{in_range_str}'."
+                    "Auto-correct calibration of motor '%s' by shifting value by %s full turns, "
+                    "from '%s' to '%s'.",
+                    name,
+                    abs(factor),
+                    out_of_range_str,
+                    in_range_str,
                 )
 
                 # A full turn corresponds to 360 degrees but also to 4096 steps for a motor resolution of 4096.
@@ -674,8 +682,8 @@ class FeetechMotorsBus:
             motor_ids = [motor_ids]
 
         assert_same_address(self.model_ctrl_table, self.motor_models, data_name)
-        addr, bytes = self.model_ctrl_table[motor_models[0]][data_name]
-        group = scs.GroupSyncRead(self.port_handler, self.packet_handler, addr, bytes)
+        addr, byte = self.model_ctrl_table[motor_models[0]][data_name]
+        group = scs.GroupSyncRead(self.port_handler, self.packet_handler, addr, byte)
         for idx in motor_ids:
             group.addParam(idx)
 
@@ -692,7 +700,7 @@ class FeetechMotorsBus:
 
         values = []
         for idx in motor_ids:
-            value = group.getData(idx, addr, bytes)
+            value = group.getData(idx, addr, byte)
             values.append(value)
 
         if return_list:
@@ -727,7 +735,7 @@ class FeetechMotorsBus:
             models.append(model)
 
         assert_same_address(self.model_ctrl_table, models, data_name)
-        addr, bytes = self.model_ctrl_table[model][data_name]
+        addr, byte = self.model_ctrl_table[model][data_name]
         group_key = get_group_sync_key(data_name, motor_names)
 
         if data_name not in self.group_readers:
@@ -737,7 +745,7 @@ class FeetechMotorsBus:
 
             # create new group reader
             self.group_readers[group_key] = scs.GroupSyncRead(
-                self.port_handler, self.packet_handler, addr, bytes
+                self.port_handler, self.packet_handler, addr, byte
             )
             for idx in motor_ids:
                 self.group_readers[group_key].addParam(idx)
@@ -755,7 +763,7 @@ class FeetechMotorsBus:
 
         values = []
         for idx in motor_ids:
-            value = self.group_readers[group_key].getData(idx, addr, bytes)
+            value = self.group_readers[group_key].getData(idx, addr, byte)
             values.append(value)
 
         values = np.array(values)
@@ -792,10 +800,10 @@ class FeetechMotorsBus:
             values = [values]
 
         assert_same_address(self.model_ctrl_table, motor_models, data_name)
-        addr, bytes = self.model_ctrl_table[motor_models[0]][data_name]
-        group = scs.GroupSyncWrite(self.port_handler, self.packet_handler, addr, bytes)
+        addr, byte = self.model_ctrl_table[motor_models[0]][data_name]
+        group = scs.GroupSyncWrite(self.port_handler, self.packet_handler, addr, byte)
         for idx, value in zip(motor_ids, values, strict=True):
-            data = convert_to_bytes(value, bytes, self.mock)
+            data = convert_to_bytes(value, byte, self.mock)
             group.addParam(idx, data)
 
         for _ in range(num_retry):
@@ -846,17 +854,17 @@ class FeetechMotorsBus:
         values = values.tolist()
 
         assert_same_address(self.model_ctrl_table, models, data_name)
-        addr, bytes = self.model_ctrl_table[model][data_name]
+        addr, byte = self.model_ctrl_table[model][data_name]
         group_key = get_group_sync_key(data_name, motor_names)
 
         init_group = data_name not in self.group_readers
         if init_group:
             self.group_writers[group_key] = scs.GroupSyncWrite(
-                self.port_handler, self.packet_handler, addr, bytes
+                self.port_handler, self.packet_handler, addr, byte
             )
 
         for idx, value in zip(motor_ids, values, strict=True):
-            data = convert_to_bytes(value, bytes, self.mock)
+            data = convert_to_bytes(value, byte, self.mock)
             if init_group:
                 self.group_writers[group_key].addParam(idx, data)
             else:
diff --git a/lerobot/common/robot_devices/robots/feetech_calibration.py b/lerobot/common/robot_devices/robots/feetech_calibration.py
index 2c1e7180e..f42aeb34f 100644
--- a/lerobot/common/robot_devices/robots/feetech_calibration.py
+++ b/lerobot/common/robot_devices/robots/feetech_calibration.py
@@ -95,6 +95,8 @@ def move_to_calibrate(
     while_move_hook=None,
 ):
     initial_pos = arm.read("Present_Position", motor_name)
+    p_present_pos = None
+    n_present_pos = None
 
     if positive_first:
         p_present_pos = move_until_block(
@@ -196,7 +198,7 @@ def run_arm_auto_calibration_so100(arm: MotorsBus, robot_type: str, arm_name: st
     calib["wrist_flex"] = move_to_calibrate(arm, "wrist_flex")
     calib["wrist_flex"] = apply_offset(calib["wrist_flex"], offset=80)
 
-    def in_between_move_hook():
+    def in_between_move_hook_elbow():
         nonlocal arm, calib
         time.sleep(2)
         ef_pos = arm.read("Present_Position", "elbow_flex")
@@ -207,14 +209,14 @@ def run_arm_auto_calibration_so100(arm: MotorsBus, robot_type: str, arm_name: st
 
     print("Calibrate elbow_flex")
     calib["elbow_flex"] = move_to_calibrate(
-        arm, "elbow_flex", positive_first=False, in_between_move_hook=in_between_move_hook
+        arm, "elbow_flex", positive_first=False, in_between_move_hook=in_between_move_hook_elbow
     )
     calib["elbow_flex"] = apply_offset(calib["elbow_flex"], offset=80 - 1024)
 
     arm.write("Goal_Position", calib["elbow_flex"]["zero_pos"] + 1024 + 512, "elbow_flex")
     time.sleep(1)
 
-    def in_between_move_hook():
+    def in_between_move_hook_shoulder():
         nonlocal arm, calib
         arm.write("Goal_Position", calib["elbow_flex"]["zero_pos"], "elbow_flex")
 
@@ -224,7 +226,7 @@ def run_arm_auto_calibration_so100(arm: MotorsBus, robot_type: str, arm_name: st
         "shoulder_lift",
         invert_drive_mode=True,
         positive_first=False,
-        in_between_move_hook=in_between_move_hook,
+        in_between_move_hook=in_between_move_hook_shoulder,
     )
     # add an 30 steps as offset to align with body
     calib["shoulder_lift"] = apply_offset(calib["shoulder_lift"], offset=1024 - 50)
diff --git a/lerobot/common/robot_devices/robots/lekiwi_remote.py b/lerobot/common/robot_devices/robots/lekiwi_remote.py
index 7bf52d21d..791dc3cc5 100644
--- a/lerobot/common/robot_devices/robots/lekiwi_remote.py
+++ b/lerobot/common/robot_devices/robots/lekiwi_remote.py
@@ -67,14 +67,14 @@ def calibrate_follower_arm(motors_bus, calib_dir_str):
         return
 
     if calib_file.exists():
-        with open(calib_file) as f:
+        with open(calib_file, encoding="utf-8") as f:
             calibration = json.load(f)
         print(f"[INFO] Loaded calibration from {calib_file}")
     else:
         print("[INFO] Calibration file not found. Running manual calibration...")
         calibration = run_arm_manual_calibration(motors_bus, "lekiwi", "follower_arm", "follower")
         print(f"[INFO] Calibration complete. Saving to {calib_file}")
-        with open(calib_file, "w") as f:
+        with open(calib_file, "w", encoding="utf-8") as f:
             json.dump(calibration, f)
     try:
         motors_bus.set_calibration(calibration)
diff --git a/lerobot/common/robot_devices/robots/manipulator.py b/lerobot/common/robot_devices/robots/manipulator.py
index 8a7c7fe66..0457eeeca 100644
--- a/lerobot/common/robot_devices/robots/manipulator.py
+++ b/lerobot/common/robot_devices/robots/manipulator.py
@@ -47,8 +47,10 @@ def ensure_safe_goal_position(
     if not torch.allclose(goal_pos, safe_goal_pos):
         logging.warning(
             "Relative goal position magnitude had to be clamped to be safe.\n"
-            f"  requested relative goal position target: {diff}\n"
-            f"    clamped relative goal position target: {safe_diff}"
+            "  requested relative goal position target: %s\n"
+            "    clamped relative goal position target: %s",
+            diff,
+            safe_diff,
         )
 
     return safe_goal_pos
@@ -245,6 +247,8 @@ class ManipulatorRobot:
             from lerobot.common.robot_devices.motors.dynamixel import TorqueMode
         elif self.robot_type in ["so100", "moss", "lekiwi"]:
             from lerobot.common.robot_devices.motors.feetech import TorqueMode
+        else:
+            raise NotImplementedError(f"Robot type {self.robot_type} is not supported")
 
         # We assume that at connection time, arms are in a rest position, and torque can
         # be safely disabled to run calibration and/or set robot preset configurations.
@@ -302,7 +306,7 @@ class ManipulatorRobot:
             arm_calib_path = self.calibration_dir / f"{arm_id}.json"
 
             if arm_calib_path.exists():
-                with open(arm_calib_path) as f:
+                with open(arm_calib_path, encoding="utf-8") as f:
                     calibration = json.load(f)
             else:
                 # TODO(rcadene): display a warning in __init__ if calibration file not available
@@ -322,7 +326,7 @@ class ManipulatorRobot:
 
                 print(f"Calibration is done! Saving calibration file '{arm_calib_path}'")
                 arm_calib_path.parent.mkdir(parents=True, exist_ok=True)
-                with open(arm_calib_path, "w") as f:
+                with open(arm_calib_path, "w", encoding="utf-8") as f:
                     json.dump(calibration, f)
 
             return calibration
diff --git a/lerobot/common/robot_devices/robots/mobile_manipulator.py b/lerobot/common/robot_devices/robots/mobile_manipulator.py
index 385e218be..f174d7a89 100644
--- a/lerobot/common/robot_devices/robots/mobile_manipulator.py
+++ b/lerobot/common/robot_devices/robots/mobile_manipulator.py
@@ -262,14 +262,14 @@ class MobileManipulator:
         arm_calib_path = self.calibration_dir / f"{arm_id}.json"
 
         if arm_calib_path.exists():
-            with open(arm_calib_path) as f:
+            with open(arm_calib_path, encoding="utf-8") as f:
                 calibration = json.load(f)
         else:
             print(f"Missing calibration file '{arm_calib_path}'")
             calibration = run_arm_manual_calibration(arm, self.robot_type, name, arm_type)
             print(f"Calibration is done! Saving calibration file '{arm_calib_path}'")
             arm_calib_path.parent.mkdir(parents=True, exist_ok=True)
-            with open(arm_calib_path, "w") as f:
+            with open(arm_calib_path, "w", encoding="utf-8") as f:
                 json.dump(calibration, f)
 
         return calibration
@@ -372,6 +372,7 @@ class MobileManipulator:
 
                 present_speed = self.last_present_speed
 
+        # TODO(Steven): [WARN] Plenty of general exceptions
         except Exception as e:
             print(f"[DEBUG] Error decoding video message: {e}")
             # If decode fails, fall back to old data