diff --git a/platformio/device/finder.py b/platformio/device/finder.py
index fc6ad3c4..621adaec 100644
--- a/platformio/device/finder.py
+++ b/platformio/device/finder.py
@@ -163,7 +163,7 @@ class SerialPortFinder:
         for item in list_serial_ports(as_objects=True):
             if item.vid == device.vid and item.pid == device.pid:
                 candidates.append(item)
-        if len(candidates) == 1:
+        if len(candidates) <= 1:
             return device.device
         for item in candidates:
             if ("GDB" if self.prefer_gdb_port else "UART") in item.description:
diff --git a/platformio/exception.py b/platformio/exception.py
index bf2cec8c..80ffb496 100644
--- a/platformio/exception.py
+++ b/platformio/exception.py
@@ -81,7 +81,7 @@ class InvalidSettingValue(UserSideException):
     MESSAGE = "Invalid value '{0}' for the setting '{1}'"
 
 
-class InvalidJSONFile(PlatformioException):
+class InvalidJSONFile(ValueError, UserSideException):
     MESSAGE = "Could not load broken JSON: {0}"
 
 
diff --git a/platformio/http.py b/platformio/http.py
index da6abb40..ee67b631 100644
--- a/platformio/http.py
+++ b/platformio/http.py
@@ -157,7 +157,10 @@ class HTTPClient:
         with ContentCache("http") as cc:
             result = cc.get(cache_key)
             if result is not None:
-                return json.loads(result)
+                try:
+                    return json.loads(result)
+                except json.JSONDecodeError:
+                    pass
             response = self.send_request(method, path, **kwargs)
             data = self._parse_json_response(response)
             cc.set(cache_key, response.text, cache_valid)
diff --git a/platformio/package/lockfile.py b/platformio/package/lockfile.py
index 3c6b2047..bc2a4347 100644
--- a/platformio/package/lockfile.py
+++ b/platformio/package/lockfile.py
@@ -15,7 +15,7 @@
 import os
 from time import sleep, time
 
-from platformio.exception import PlatformioException
+from platformio.exception import UserSideException
 
 LOCKFILE_TIMEOUT = 3600  # in seconds, 1 hour
 LOCKFILE_DELAY = 0.2
@@ -36,11 +36,11 @@ except ImportError:
         LOCKFILE_CURRENT_INTERFACE = None
 
 
-class LockFileExists(PlatformioException):
+class LockFileExists(UserSideException):
     pass
 
 
-class LockFileTimeoutError(PlatformioException):
+class LockFileTimeoutError(UserSideException):
     pass
 
 
diff --git a/platformio/package/manager/_registry.py b/platformio/package/manager/_registry.py
index 494e2d24..4c339be8 100644
--- a/platformio/package/manager/_registry.py
+++ b/platformio/package/manager/_registry.py
@@ -25,12 +25,13 @@ from platformio.registry.mirror import RegistryFileMirrorIterator
 
 class PackageManagerRegistryMixin:
     def install_from_registry(self, spec, search_qualifiers=None):
+        package = version = None
         if spec.owner and spec.name and not search_qualifiers:
             package = self.fetch_registry_package(spec)
             if not package:
                 raise UnknownPackageError(spec.humanize())
             version = self.pick_best_registry_version(package["versions"], spec)
-        else:
+        elif spec.id or spec.name:
             packages = self.search_registry_packages(spec, search_qualifiers)
             if not packages:
                 raise UnknownPackageError(spec.humanize())
diff --git a/platformio/platform/board.py b/platformio/platform/board.py
index 4cd102d1..78d48943 100644
--- a/platformio/platform/board.py
+++ b/platformio/platform/board.py
@@ -17,7 +17,7 @@ import os
 from platformio import fs, util
 from platformio.compat import MISSING
 from platformio.debug.exception import DebugInvalidOptionsError, DebugSupportError
-from platformio.exception import UserSideException
+from platformio.exception import InvalidJSONFile, UserSideException
 from platformio.platform.exception import InvalidBoardManifest
 
 
@@ -28,7 +28,7 @@ class PlatformBoardConfig:
         self.manifest_path = manifest_path
         try:
             self._manifest = fs.load_json(manifest_path)
-        except ValueError as exc:
+        except InvalidJSONFile as exc:
             raise InvalidBoardManifest(manifest_path) from exc
         if not set(["name", "url", "vendor"]) <= set(self._manifest):
             raise UserSideException(