diff --git a/tests/aslts/src/runtime/cntl/runmode.asl b/tests/aslts/src/runtime/cntl/runmode.asl
index dbf3ba3e1..5ccb3b0fa 100644
--- a/tests/aslts/src/runtime/cntl/runmode.asl
+++ b/tests/aslts/src/runtime/cntl/runmode.asl
@@ -560,7 +560,7 @@ Method(SET2, 1) {
 	Case (5) {
 		Store(0, y135)
 		Store(1, y900)
-		Store(0, y901)
+		Store(1, y901) // Predicate generates Implicit Return since ACPICA release 20080926
 		Store(1, FLG9)
 		Store(1, y263)
 		Store(1, y275)
diff --git a/tests/aslts/src/runtime/collections/Identity2MS/abbu/misc/ms1.asl b/tests/aslts/src/runtime/collections/Identity2MS/abbu/misc/ms1.asl
index ba08247c0..6ef1c28ff 100644
--- a/tests/aslts/src/runtime/collections/Identity2MS/abbu/misc/ms1.asl
+++ b/tests/aslts/src/runtime/collections/Identity2MS/abbu/misc/ms1.asl
@@ -2345,8 +2345,15 @@ Method(ms23, 1)
 
 		if (SLCK) {
 			if (CH03(ts, z179, 0x096, 0, 0)) {return}
-			if (LNotEqual(i000, 0xabcd000f)) {
-				err(ts, z179, 0x097, 0, 0, i000, 0xabcd000f)
+
+			//y901: Predicate generates Implicit Return since ACPICA release 20080926
+			if (y901) {
+				Store(0, Local0)
+			} else {
+				Store(0xabcd000f, Local0)
+			}
+			if (LNotEqual(i000, Local0)) {
+				err(ts, z179, 0x097, 0, 0, i000, Local0)
 			}
 		} else {
 			CH04(ts, 0, 0xff, z179, 0x098, 0, 0)
@@ -2376,8 +2383,15 @@ Method(ms23, 1)
 
 		if (SLCK) {
 			if (CH03(ts, z179, 0x099, 0, 0)) {return}
-			if (LNotEqual(i000, 0xabcd000d)) {
-				err(ts, z179, 0x09a, 0, 0, i000, 0xabcd000d)
+
+			//y901: Predicate generates Implicit Return since ACPICA release 20080926
+			if (y901) {
+				Store(0, Local0)
+			} else {
+				Store(0xabcd000d, Local0)
+			}
+			if (LNotEqual(i000, Local0)) {
+				err(ts, z179, 0x09a, 0, 0, i000, Local0)
 			}
 		} else {
 			CH04(ts, 0, 0xff, z179, 0x09b, 0, 0)
@@ -2408,8 +2422,15 @@ Method(ms23, 1)
 
 		if (SLCK) {
 			if (CH03(ts, z179, 0x09c, 0, 0)) {return}
-			if (LNotEqual(i000, 0xabcd000e)) {
-				err(ts, z179, 0x09d, 0, 0, i000, 0xabcd000e)
+
+			//y901: Predicate generates Implicit Return since ACPICA release 20080926
+			if (y901) {
+				Store(0, Local0)
+			} else {
+				Store(0xabcd000e, Local0)
+			}
+			if (LNotEqual(i000, Local0)) {
+				err(ts, z179, 0x09d, 0, 0, i000, Local0)
 			}
 		} else {
 			CH04(ts, 0, 0xff, z179, 0x09e, 0, 0)
diff --git a/tests/aslts/src/runtime/collections/bdemo/ACPICA/0186/DECL.asl b/tests/aslts/src/runtime/collections/bdemo/ACPICA/0186/DECL.asl
index 21da4b7b3..f8578aa4f 100644
--- a/tests/aslts/src/runtime/collections/bdemo/ACPICA/0186/DECL.asl
+++ b/tests/aslts/src/runtime/collections/bdemo/ACPICA/0186/DECL.asl
@@ -31,7 +31,7 @@
 /*
  * Bug 186:
  *
- * SUMMARY: The predicate value of If/While operations is not implicitly returned in slack mode
+ * SUMMARY: The predicate value of If/While operations is implicitly returned in slack mode
  */
 
 
@@ -82,8 +82,15 @@ Method(mf6d)
 
 	if (SLCK) {
 		CH03("", 0, 0x001, 0, 0)
-		if (LNotEqual(i000, 0xabcd0000)) {
-			err("", zFFF, 0x002, 0, 0, i000, 0xabcd0000)
+
+		//y901: Predicate generates Implicit Return since ACPICA release 20080926	
+		if (y901) {
+			Store(0, Local0)
+		} else {
+			Store(0xabcd0000, Local0)
+		}
+		if (LNotEqual(i000, Local0)) {
+			err("", zFFF, 0x002, 0, 0, i000, Local0)
 		}
 	} else {
 		CH07("", 0, 0xff, 0, 0x003, 0, 0)
@@ -99,8 +106,15 @@ Method(mf6d)
 
 	if (SLCK) {
 		CH03("", 0, 0x005, 0, 0)
-		if (LNotEqual(i000, 0xabcd0001)) {
-			err("", zFFF, 0x006, 0, 0, i000, 0xabcd0001)
+
+		//y901: Predicate generates Implicit Return since ACPICA release 20080926	
+		if (y901) {
+			Store(0, Local0)
+		} else {
+			Store(0xabcd0001, Local0)
+		}
+		if (LNotEqual(i000, Local0)) {
+			err("", zFFF, 0x006, 0, 0, i000, Local0)
 		}
 	} else {
 		CH07("", 0, 0xff, 0, 0x007, 0, 0)
@@ -116,8 +130,15 @@ Method(mf6d)
 
 	if (SLCK) {
 		CH03("", 0, 0x009, 0, 0)
-		if (LNotEqual(i000, 0xabcd0002)) {
-			err("", zFFF, 0x00a, 0, 0, i000, 0xabcd0002)
+
+		//y901: Predicate generates Implicit Return since ACPICA release 20080926	
+		if (y901) {
+			Store(0, Local0)
+		} else {
+			Store(0xabcd0002, Local0)
+		}
+		if (LNotEqual(i000, Local0)) {
+			err("", zFFF, 0x00a, 0, 0, i000, Local0)
 		}
 	} else {
 		CH07("", 0, 0xff, 0, 0x00b, 0, 0)