diff --git a/Services/Iec61850ValueFormatter.cs b/Services/Iec61850ValueFormatter.cs
index 522aa0aa..d629f29a 100644
--- a/Services/Iec61850ValueFormatter.cs
+++ b/Services/Iec61850ValueFormatter.cs
@@ -7,6 +7,13 @@ public static class Iec61850ValueFormatter
 {
     public static string Format(object? value, string dataType, string unit)
     {
+        // Compatibility guard for ARIEC61850 builds that still expose an SPS-like
+        // DataObject report value as one rendered CDC structure instead of the
+        // projected stVal leaf.  Keep this deliberately narrow: stVal must be the
+        // first named field and must be a Boolean.  Other structures remain intact.
+        if (TryExtractStructuredBooleanStVal(value, out var structuredStVal))
+            value = structuredStVal;
+
         if (IsDbposDataType(dataType) && TryNormalizeDbpos(value, out var dbpos))
             return FormatDbpos(dbpos);
 
@@ -115,6 +122,19 @@ private static bool TryParseDbposText(string text, out int code)
         }
     }
 
+    private static bool TryExtractStructuredBooleanStVal(object? value, out bool status)
+    {
+        status = false;
+        if (value is not string text || string.IsNullOrWhiteSpace(text))
+            return false;
+
+        var match = Regex.Match(
+            text,
+            @"^\s*Structure\(\s*\d+\s*\)\s*\{\s*stVal\s*=\s*(true|false)\b",
+            RegexOptions.IgnoreCase | RegexOptions.CultureInvariant);
+        return match.Success && bool.TryParse(match.Groups[1].Value, out status);
+    }
+
     private static bool TryParseBits(string bits, out int code)
     {
         code = bits switch
diff --git a/engines/ARIEC61850.lock.json b/engines/ARIEC61850.lock.json
index cb321207..ed6a1666 100644
--- a/engines/ARIEC61850.lock.json
+++ b/engines/ARIEC61850.lock.json
@@ -2,7 +2,7 @@
   "schemaVersion": 1,
   "repository": "masarray/ARIEC61850",
   "ref": "main",
-  "commit": "761fa0df9ca84fbe15352d2670f03fddbe8784ba",
-  "sourcePullRequest": 78,
-  "purpose": "Pins the ARIEC61850 engine used by ARSAS. PR #76 preserves unresolved static DataSet members, PR #77 canonicalizes cross-logical-device SCL references, and PR #78 makes mandatory Signal Selection inventory protocol-member-centric: exactly one descriptor per static DataSet member while keeping resolved runtime primary leaves separate from the original FCDA/FCD identity."
+  "commit": "1ed53ab3252902f680d76adbadd25790bf6f8ca4",
+  "sourcePullRequest": 79,
+  "purpose": "Pins the ARIEC61850 engine used by ARSAS. PR #76 preserves unresolved static DataSet members, PR #77 canonicalizes cross-logical-device SCL references, PR #78 keeps one descriptor per static DataSet member while separating resolved runtime primary leaves from the original FCDA/FCD identity, and PR #79 projects generic Boolean status structures {stVal, q, t} to the scalar stVal leaf while preserving quality/timestamp and raw-structure diagnostics for unrecognized non-Boolean structures."
 }
diff --git a/tests/ARSAS.Tests/Iec61850ValueFormatterTests.cs b/tests/ARSAS.Tests/Iec61850ValueFormatterTests.cs
new file mode 100644
index 00000000..ddbe66b6
--- /dev/null
+++ b/tests/ARSAS.Tests/Iec61850ValueFormatterTests.cs
@@ -0,0 +1,36 @@
+using ArIED61850Tester.Services;
+
+namespace ARSAS.Tests;
+
+public sealed class Iec61850ValueFormatterTests
+{
+    [Fact]
+    public void Format_Extracts_Boolean_StVal_From_Legacy_Report_Structure()
+    {
+        const string value = "Structure(3) {stVal=false, q=Quality{V=1,D=0,Ov=0,F=0,Osc=0,B=0,Oot=0,Incon=0,Ina=0,src=0,test=0,opBlk=0}, t=BinaryTime(2026-08-15 16:11:57.723, Q=0x0A, ext=True)}";
+
+        var formatted = Iec61850ValueFormatter.Format(value, "Boolean", string.Empty);
+
+        Assert.Equal("False", formatted);
+    }
+
+    [Fact]
+    public void Format_Extracts_True_Boolean_StVal_From_Legacy_Report_Structure()
+    {
+        const string value = "Structure(3) {stVal=true, q=Quality{V=1,D=0}, t=BinaryTime(2026-08-15 16:11:57.723, Q=0x0A, ext=True)}";
+
+        var formatted = Iec61850ValueFormatter.Format(value, "Boolean", string.Empty);
+
+        Assert.Equal("True", formatted);
+    }
+
+    [Fact]
+    public void Format_Does_Not_Collapse_NonStVal_Structures()
+    {
+        const string value = "Structure(3) {mag=123.4, q=Quality{V=1,D=0}, t=BinaryTime(2026-08-15 16:11:57.723, Q=0x0A, ext=True)}";
+
+        var formatted = Iec61850ValueFormatter.Format(value, "Float", "V");
+
+        Assert.Equal(value, formatted);
+    }
+}
diff --git a/tests/ARSAS.Tests/OfflineDataSetSignalSelectionRegressionTests.cs b/tests/ARSAS.Tests/OfflineDataSetSignalSelectionRegressionTests.cs
index 1b18e004..1f9c43e4 100644
--- a/tests/ARSAS.Tests/OfflineDataSetSignalSelectionRegressionTests.cs
+++ b/tests/ARSAS.Tests/OfflineDataSetSignalSelectionRegressionTests.cs
@@ -68,13 +68,14 @@ public void SignalSelectionRecovery_RunsAgainAfterLegacyConstructorDisplayPrepar
     }
 
     [Fact]
-    public void EngineLock_PinsMemberCentricStaticDataSetInventory()
+    public void EngineLock_PinsMergedReportProjectionEngineWithoutLosingMemberCentricInventory()
     {
         var source = File.ReadAllText(FindRepoFile("engines/ARIEC61850.lock.json"));
 
-        Assert.Contains("761fa0df9ca84fbe15352d2670f03fddbe8784ba", source, StringComparison.OrdinalIgnoreCase);
-        Assert.Contains("\"sourcePullRequest\": 78", source, StringComparison.Ordinal);
+        Assert.Contains("1ed53ab3252902f680d76adbadd25790bf6f8ca4", source, StringComparison.OrdinalIgnoreCase);
+        Assert.Contains("\"sourcePullRequest\": 79", source, StringComparison.Ordinal);
         Assert.Contains("one descriptor per static DataSet member", source, StringComparison.OrdinalIgnoreCase);
+        Assert.Contains("generic Boolean status structures", source, StringComparison.OrdinalIgnoreCase);
     }
 
     [Fact]