diff --git a/usrc/subboards/subboard90_optical_module/optical_module_v2.cpp b/usrc/subboards/subboard90_optical_module/optical_module_v2.cpp
index a0048fd..ea2605e 100644
--- a/usrc/subboards/subboard90_optical_module/optical_module_v2.cpp
+++ b/usrc/subboards/subboard90_optical_module/optical_module_v2.cpp
@@ -300,7 +300,10 @@ int32_t OpticalModuleV2::a8000_optical_read_raw(int32_t index, uint8_t* data, in
   if (sector_size > *len) return err::kbuffer_not_enough;
   uint16_t add = index * sector_size;
 
-  if (add >= rawsize) return err::kparam_out_of_range;
+  if (add >= rawsize) {
+    *len = 0;
+    return 0;
+  }
 
   if (add + sector_size > rawsize) {  // rawsize 127 sector_size 128 add = 0
     *len = rawsize - add;