diff --git a/src/extra/libs/fsdrv/lv_fs_posix.c b/src/extra/libs/fsdrv/lv_fs_posix.c
index 753c0227c5..7f91c8612c 100644
--- a/src/extra/libs/fsdrv/lv_fs_posix.c
+++ b/src/extra/libs/fsdrv/lv_fs_posix.c
@@ -151,7 +151,7 @@ static lv_fs_res_t fs_read(lv_fs_drv_t * drv, void * file_p, void * buf, uint32_
 {
     LV_UNUSED(drv);
     *br = read((lv_uintptr_t)file_p, buf, btr);
-    return LV_FS_RES_OK;
+    return (int32_t)*br < 0 ? LV_FS_RES_UNKNOWN : LV_FS_RES_OK;
 }
 
 /**
@@ -167,7 +167,7 @@ static lv_fs_res_t fs_write(lv_fs_drv_t * drv, void * file_p, const void * buf,
 {
     LV_UNUSED(drv);
     *bw = write((lv_uintptr_t)file_p, buf, btw);
-    return LV_FS_RES_OK;
+    return (int32_t)*bw ? LV_FS_RES_UNKNOWN : LV_FS_RES_OK;
 }
 
 /**
diff --git a/src/extra/libs/fsdrv/lv_fs_stdio.c b/src/extra/libs/fsdrv/lv_fs_stdio.c
index e14d2ce1c3..5184e12db3 100644
--- a/src/extra/libs/fsdrv/lv_fs_stdio.c
+++ b/src/extra/libs/fsdrv/lv_fs_stdio.c
@@ -152,7 +152,7 @@ static lv_fs_res_t fs_read(lv_fs_drv_t * drv, void * file_p, void * buf, uint32_
 {
     LV_UNUSED(drv);
     *br = fread(buf, 1, btr, file_p);
-    return LV_FS_RES_OK;
+    return (int32_t)*br < 0 ? LV_FS_RES_UNKNOWN : LV_FS_RES_OK;
 }
 
 /**
@@ -168,7 +168,7 @@ static lv_fs_res_t fs_write(lv_fs_drv_t * drv, void * file_p, const void * buf,
 {
     LV_UNUSED(drv);
     *bw = fwrite(buf, 1, btw, file_p);
-    return LV_FS_RES_OK;
+    return (int32_t)*bw ? LV_FS_RES_UNKNOWN : LV_FS_RES_OK;
 }
 
 /**