diff --git a/interface/src/tfm_sst_api.c b/interface/src/tfm_sst_api.c
index 2722c67..c7796d0 100644
--- a/interface/src/tfm_sst_api.c
+++ b/interface/src/tfm_sst_api.c
@@ -44,7 +44,7 @@
         return PSA_PS_ERROR_OPERATION_FAILED;
     }
 
-    status = psa_call(handle, in_vec, IOVEC_LEN(in_vec), out_vec,
+    status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec), out_vec,
                       IOVEC_LEN(out_vec));
 
     psa_close(handle);
@@ -92,7 +92,7 @@
         return PSA_PS_ERROR_OPERATION_FAILED;
     }
 
-    status = psa_call(handle, in_vec, IOVEC_LEN(in_vec), out_vec,
+    status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec), out_vec,
                       IOVEC_LEN(out_vec));
 
     psa_close(handle);
@@ -137,7 +137,7 @@
         return PSA_PS_ERROR_OPERATION_FAILED;
     }
 
-    status = psa_call(handle, in_vec, IOVEC_LEN(in_vec), out_vec,
+    status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec), out_vec,
                       IOVEC_LEN(out_vec));
 
     psa_close(handle);
@@ -181,7 +181,7 @@
         return PSA_PS_ERROR_OPERATION_FAILED;
     }
 
-    status = psa_call(handle, in_vec, IOVEC_LEN(in_vec), out_vec,
+    status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec), out_vec,
                       IOVEC_LEN(out_vec));
 
     psa_close(handle);
@@ -247,7 +247,7 @@
         return support_flags;
     }
 
-    (void)psa_call(handle, NULL, 0, out_vec, IOVEC_LEN(out_vec));
+    (void)psa_call(handle, PSA_IPC_CALL, NULL, 0, out_vec, IOVEC_LEN(out_vec));
 
     psa_close(handle);
 #else