diff --git a/src/osal/lv_freertos.c b/src/osal/lv_freertos.c
index ae16340e7..73dd7c564 100644
--- a/src/osal/lv_freertos.c
+++ b/src/osal/lv_freertos.c
@@ -252,7 +252,7 @@ lv_res_t lv_thread_sync_signal(lv_thread_sync_t * pxCond)
                0,
                ulLocalWaitingThreads)) {
             /* Unblock all. */
-            for(int i = 0; i < ulLocalWaitingThreads; i++) {
+            for(uint32_t i = 0; i < ulLocalWaitingThreads; i++) {
                 xSemaphoreGive(pxCond->xCondWaitSemaphore);
             }