diff --git a/src/xrt/state_trackers/oxr/oxr_api_session.c b/src/xrt/state_trackers/oxr/oxr_api_session.c
index 034f6ab6611d3fd4e500c35d4a6c0e053ea776a8..62cee638e7a5b7d020fe6e993171663f0d1f0d89 100644
--- a/src/xrt/state_trackers/oxr/oxr_api_session.c
+++ b/src/xrt/state_trackers/oxr/oxr_api_session.c
@@ -94,8 +94,8 @@ oxr_xrWaitFrame(XrSession session,
 	struct oxr_logger log;
 	OXR_VERIFY_SESSION_AND_INIT_LOG(&log, session, sess, "xrWaitFrame");
 	if (sess->compositor == NULL) {
-		return oxr_error(&log, XR_ERROR_VALIDATION_FAILURE,
-		                 "xrWaitFrame is illegal headless sessions");
+		return oxr_error(&log, XR_ERROR_GRAPHICS_DEVICE_INVALID,
+		                 "xrWaitFrame is illegal in headless sessions");
 	}
 	OXR_VERIFY_ARG_TYPE_AND_NULL(&log, frameState, XR_TYPE_FRAME_STATE);
 	OXR_VERIFY_ARG_NOT_NULL(&log, frameState);
@@ -109,8 +109,11 @@ oxr_xrBeginFrame(XrSession session, const XrFrameBeginInfo* frameBeginInfo)
 	struct oxr_session* sess;
 	struct oxr_logger log;
 	OXR_VERIFY_SESSION_AND_INIT_LOG(&log, session, sess, "xrBeginFrame");
-	OXR_VERIFY_ARG_TYPE_AND_NULL(&log, frameBeginInfo,
-	                             XR_TYPE_FRAME_BEGIN_INFO);
+	// NULL explicitly allowed here because it's a basically empty struct.
+	if (frameBeginInfo != NULL) {
+		OXR_VERIFY_ARG_TYPE_AND_NULL(&log, frameBeginInfo,
+		                             XR_TYPE_FRAME_BEGIN_INFO);
+	}
 
 	return oxr_session_frame_begin(&log, sess);
 }