diff --git a/HISTORY.rst b/HISTORY.rst
index 17be25e1..7a6a93cd 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -20,6 +20,8 @@ test-driven methodologies, and modern toolchains for unrivaled success.
 6.1.13 (2024-??-??)
 ~~~~~~~~~~~~~~~~~~~
 
+* Expanded support for SCons variables declared in the legacy format ``${SCONS_VARNAME}`` (`issue #4828 <https://github.com/platformio/platformio-core/issues/4828>`_)
+
 6.1.12 (2024-01-10)
 ~~~~~~~~~~~~~~~~~~~
 
diff --git a/platformio/project/config.py b/platformio/project/config.py
index 3d92a5ae..f138f26c 100644
--- a/platformio/project/config.py
+++ b/platformio/project/config.py
@@ -164,6 +164,7 @@ class ProjectConfigBase:
 
     @staticmethod
     def get_section_scope(section):
+        assert section
         return section.split(":", 1)[0] if ":" in section else section
 
     def walk_options(self, root_section):
@@ -343,8 +344,11 @@ class ProjectConfigBase:
         section, option = match.group(1), match.group(2)
 
         # handle built-in variables
-        if section is None and option in self.BUILTIN_VARS:
-            return self.BUILTIN_VARS[option]()
+        if section is None:
+            if option in self.BUILTIN_VARS:
+                return self.BUILTIN_VARS[option]()
+            # SCons varaibles
+            return f"${option}"
 
         # handle system environment variables
         if section == "sysenv":
diff --git a/tests/project/test_config.py b/tests/project/test_config.py
index 3f368fe1..c15aa7bc 100644
--- a/tests/project/test_config.py
+++ b/tests/project/test_config.py
@@ -657,7 +657,9 @@ build_dir = /tmp/pio-$PROJECT_HASH
 data_dir = $PROJECT_DIR/assets
 
 [env:myenv]
-build_flags = -D UTIME=${UNIX_TIME}
+build_flags =
+    -D UTIME=${UNIX_TIME}
+    -I ${PROJECTSRC_DIR}/hal
 test_testing_command =
     ${platformio.packages_dir}/tool-simavr/bin/simavr
      -m
@@ -672,6 +674,7 @@ test_testing_command =
         os.path.join("$PROJECT_DIR", "assets")
     )
     assert config.get("env:myenv", "build_flags")[0][-10:].isdigit()
+    assert config.get("env:myenv", "build_flags")[1] == "-I $PROJECTSRC_DIR/hal"
     testing_command = config.get("env:myenv", "test_testing_command")
     assert "$" not in " ".join(testing_command)