diff --git a/trunk/bootrom/build/libraries/os/common/os_alarm.c b/trunk/bootrom/build/libraries/os/common/os_alarm.c
index c9f1507..2f37fcb 100644
--- a/trunk/bootrom/build/libraries/os/common/os_alarm.c
+++ b/trunk/bootrom/build/libraries/os/common/os_alarm.c
@@ -64,7 +64,11 @@ static void i_osSetTimer(OSAlarm *alarm)
     delta = (s64)(alarm->fire - tick);
 
     //---- let timer be disable
+#ifdef SDK_ARM11
+    osClearTimerEventFlag(OSi_ALARM_TIMER);
+#else // SDK_ARM9
     osSetTimerControl(OSi_ALARM_TIMER, 0);
+#endif // SDK_ARM9
 
     //---- set interrupt callback
     osSetInterruptHandler( OSi_ALARM_IE_TIMER_ID, i_osArrangeTimer );
diff --git a/trunk/bootrom/include/brom/os/common/tick.h b/trunk/bootrom/include/brom/os/common/tick.h
index 0149ac3..b010d94 100644
--- a/trunk/bootrom/include/brom/os/common/tick.h
+++ b/trunk/bootrom/include/brom/os/common/tick.h
@@ -53,7 +53,7 @@ extern  void i_osSetTick( u64 );
 #ifdef SDK_ARM11
 #define OS_TICK_CLOCK                  HW_CPU_CLOCK
 #define OS_TICK_PRESCALE               1
-#define OS_TICK_HI_SHIFT               24               // 2の累乗単位でチック管理するのであれば32は指定できない（ロード値0では割り込みが発生しないため。最大31）
+#define OS_TICK_HI_SHIFT               28               // 2の累乗単位でチック管理するのであれば32は指定できない（ロード値0では割り込みが発生しないため。最大31）
 #define OS_TICK_HI_LSB                 (1ULL<<OS_TICK_HI_SHIFT)
 #define OS_TICK_LO_MASK                ((u32)(OS_TICK_HI_LSB-1))
 #define OS_TICK_LO_MSB                 ((u32)(OS_TICK_HI_LSB>>1))