diff --git a/build/libraries/fatfs/ARM9/src/fatfs_firm.c b/build/libraries/fatfs/ARM9/src/fatfs_firm.c
index 730649a1..23d0f8ff 100644
--- a/build/libraries/fatfs/ARM9/src/fatfs_firm.c
+++ b/build/libraries/fatfs/ARM9/src/fatfs_firm.c
@@ -21,8 +21,6 @@
 
 void FATFS_InitFIRM( void )
 {
-    MI_CpuClearFast( (void*)HW_FIRM_FATFS_COMMAND_BUFFER, HW_FIRM_FATFS_COMMAND_BUFFER_SIZE );
-    MI_CpuClearFast( (void*)HW_FIRM_FATFS_ARCHNAME_LIST, HW_FIRM_FATFS_ARCHNAME_LIST_SIZE );
     FATFSiCommandBuffer = (void*)HW_FIRM_FATFS_COMMAND_BUFFER;
     FATFSiArcnameList = (void*)HW_FIRM_FATFS_ARCHNAME_LIST;
     FATFS_Init();
diff --git a/build/libraries/fs/ARM9/src/fs_firm.c b/build/libraries/fs/ARM9/src/fs_firm.c
index f5f14e34..394dfbff 100644
--- a/build/libraries/fs/ARM9/src/fs_firm.c
+++ b/build/libraries/fs/ARM9/src/fs_firm.c
@@ -36,6 +36,8 @@
  *---------------------------------------------------------------------------*/
 void FS_InitFIRM( void )
 {
+    // FS/FATFSの全メモリクリア
+    MI_CpuClearFast((void*)HW_FIRM_FATFS_ARCHNAME_LIST, HW_FIRM_FS_FATFS_ASYNC_REQUEST_END - HW_FIRM_FATFS_ARCHNAME_LIST);
     FATFS_InitFIRM();
     FS_Init( FS_DMA_NOT_USE );
 }