diff --git a/src/os/portable/os-impl-bsd-select.c b/src/os/portable/os-impl-bsd-select.c
index bae652aac..70575e6c9 100644
--- a/src/os/portable/os-impl-bsd-select.c
+++ b/src/os/portable/os-impl-bsd-select.c
@@ -92,9 +92,9 @@ static int32 OS_FdSet_ConvertIn_Impl(int *os_maxfd, fd_set *os_set, const OS_FdS
             if ((objids & 0x01) != 0 && id < OS_MAX_NUM_OPEN_FILES)
             {
                 osfd = OS_impl_filehandle_table[id].fd;
-                if (osfd >= 0 && OS_impl_filehandle_table[id].selectable)
+                if (osfd >= 0)
                 {
-                    if (osfd >= FD_SETSIZE)
+                    if (osfd >= FD_SETSIZE || !OS_impl_filehandle_table[id].selectable)
                     {
                         /* out of range of select() implementation */
                         status = OS_ERR_OPERATION_NOT_SUPPORTED;
diff --git a/src/unit-test-coverage/portable/src/coveragetest-bsd-select.c b/src/unit-test-coverage/portable/src/coveragetest-bsd-select.c
index 653f6aed0..eb88520c4 100644
--- a/src/unit-test-coverage/portable/src/coveragetest-bsd-select.c
+++ b/src/unit-test-coverage/portable/src/coveragetest-bsd-select.c
@@ -112,10 +112,13 @@ void Test_OS_SelectMultiple_Impl(void)
     UT_PortablePosixIOTest_Set_Selectable(UT_INDEX_0, true);
 
     memset(&ReadSet, 0, sizeof(ReadSet));
-    memset(&WriteSet, 0xff, sizeof(WriteSet));
+    memset(&WriteSet, 0, sizeof(WriteSet));
+    WriteSet.object_ids[0] = 1;
     OSAPI_TEST_FUNCTION_RC(OS_SelectMultiple_Impl, (&ReadSet, &WriteSet, 0), OS_SUCCESS);
-    memset(&ReadSet, 0xff, sizeof(ReadSet));
+
+    memset(&ReadSet, 0, sizeof(ReadSet));
     memset(&WriteSet, 0, sizeof(WriteSet));
+    ReadSet.object_ids[0] = 1;
     UT_SetDefaultReturnValue(UT_KEY(OCS_select), 0);
     OSAPI_TEST_FUNCTION_RC(OS_SelectMultiple_Impl, (&ReadSet, &WriteSet, 1), OS_ERROR_TIMEOUT);
 
@@ -136,6 +139,13 @@ void Test_OS_SelectMultiple_Impl(void)
     memset(&WriteSet, 0xff, sizeof(WriteSet));
     OSAPI_TEST_FUNCTION_RC(OS_SelectMultiple_Impl, (&ReadSet, &WriteSet, 0), OS_ERR_OPERATION_NOT_SUPPORTED);
 
+    /* Test cases where additional bits are set in the OS_FdSet */
+    UT_PortablePosixIOTest_Set_FD(UT_INDEX_0, 0);
+    UT_PortablePosixIOTest_Set_Selectable(UT_INDEX_0, true);
+    memset(&ReadSet, 0xff, sizeof(ReadSet));
+    memset(&WriteSet, 0xff, sizeof(WriteSet));
+    OSAPI_TEST_FUNCTION_RC(OS_SelectMultiple_Impl, (&ReadSet, &WriteSet, 0), OS_ERR_OPERATION_NOT_SUPPORTED);
+
 } /* end OS_SelectMultiple_Impl */
 
 /* ------------------- End of test cases --------------------------------------*/