diff --git a/easyflash/src/ef_log.c b/easyflash/src/ef_log.c
index 9d2b8c6..49e9d7c 100644
--- a/easyflash/src/ef_log.c
+++ b/easyflash/src/ef_log.c
@@ -463,8 +463,7 @@ static uint32_t log_index2addr(size_t index) {
         if (log_start_addr + index + header_total_offset < log_area_start_addr + LOG_AREA_SIZE) {
             return log_start_addr + index + header_total_offset;
         } else {
-            return log_start_addr + index + header_total_offset - LOG_AREA_SIZE;
-
+            return (log_start_addr + index + header_total_offset) % LOG_AREA_SIZE;
         }
     }
 }
@@ -490,8 +489,14 @@ EfErrCode ef_log_read(size_t index, uint32_t *log, size_t size) {
         return result;
     }
 
-    EF_ASSERT(size % 4 == 0);
-    EF_ASSERT(index < cur_using_size);
+    if (size % 4 == 0) {
+        EF_DEBUG("Error: size must be word aligned.");
+        return EF_READ_ERR;
+    }
+    if (index < cur_using_size) {
+        EF_DEBUG("Error: index out of ranges, current using size is %d", cur_using_size);
+        return EF_READ_ERR;
+    }
 
     if (index + size > cur_using_size) {
         EF_DEBUG("Warning: Log read size out of bound. Cut read size.\n");