diff --git a/sdk/include/ndk/rtlfuncs.h b/sdk/include/ndk/rtlfuncs.h
index c18ef849ec9..20913ab01d2 100644
--- a/sdk/include/ndk/rtlfuncs.h
+++ b/sdk/include/ndk/rtlfuncs.h
@@ -3193,14 +3193,14 @@ RtlInitializeCriticalSectionAndSpinCount(
 );
 
 NTSYSAPI
-ULONG
+LOGICAL
 NTAPI
 RtlIsCriticalSectionLocked(
     _In_ PRTL_CRITICAL_SECTION CriticalSection
 );
 
 NTSYSAPI
-ULONG
+LOGICAL
 NTAPI
 RtlIsCriticalSectionLockedByThread(
     _In_ PRTL_CRITICAL_SECTION CriticalSection
diff --git a/sdk/lib/rtl/critical.c b/sdk/lib/rtl/critical.c
index 69bf3eede5d..f355e5ddfef 100644
--- a/sdk/lib/rtl/critical.c
+++ b/sdk/lib/rtl/critical.c
@@ -863,14 +863,14 @@ RtlCheckForOrphanedCriticalSections(HANDLE ThreadHandle)
     UNIMPLEMENTED;
 }
 
-ULONG
+LOGICAL
 NTAPI
 RtlIsCriticalSectionLocked(PRTL_CRITICAL_SECTION CriticalSection)
 {
     return CriticalSection->RecursionCount != 0;
 }
 
-ULONG
+LOGICAL
 NTAPI
 RtlIsCriticalSectionLockedByThread(PRTL_CRITICAL_SECTION CriticalSection)
 {