diff --git a/libupgrade/hmx_upgrade_nvram.c b/libupgrade/hmx_upgrade_nvram.c
index 2c07b7a..c3434d6 100644
--- a/libupgrade/hmx_upgrade_nvram.c
+++ b/libupgrade/hmx_upgrade_nvram.c
@@ -869,7 +869,7 @@
     return DRV_ERR_OUTOFMEMORY;
   }
 
-  int fieldLen = 0;
+  unsigned int fieldLen = 0;
   // Need to use fieldLen for actual field length because pLen is always
   // <= nDataSize. If input data size is shorter this may falsely skip hnvram
   // writing.
@@ -938,7 +938,7 @@
   return errCode;
 }
 
-DRV_Error HMX_NVRAM_GetLength(NVRAM_FIELD_T field, int *pLen)
+DRV_Error HMX_NVRAM_GetLength(NVRAM_FIELD_T field, unsigned int *pLen)
 {
   DRV_Error errCode = DRV_ERR;
   unsigned char szFileName[MAX_NVRAM_FILENAME_LENGTH];
diff --git a/libupgrade/hmx_upgrade_nvram.h b/libupgrade/hmx_upgrade_nvram.h
index 3e638fe..8ae6f02 100644
--- a/libupgrade/hmx_upgrade_nvram.h
+++ b/libupgrade/hmx_upgrade_nvram.h
@@ -158,7 +158,7 @@
                                    void *data, int nDataSize);
 DRV_Error       HMX_NVRAM_SetField(NVRAM_FIELD_T field, unsigned int offset,
                                    void *data, int nDataSize);
-DRV_Error       HMX_NVRAM_GetLength(NVRAM_FIELD_T field, int *pLen);
+DRV_Error       HMX_NVRAM_GetLength(NVRAM_FIELD_T field, unsigned int *pLen);
 DRV_Error       HMX_NVRAM_Remove(HMX_NVRAM_PARTITION_E partition,
                                  unsigned char *pName);
 DRV_Error       HMX_NVRAM_Dir(void);