diff --git a/ChangeLog b/ChangeLog
index d3f44ae..d42d18a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,31 @@
 2012-05-25  Niibe Yutaka  <gniibe@fsij.org>
 
+	* boards/STM8S_DISCOVERY/board.h (SET_USB_CONDITION)
+	(SET_LED_CONDITION, GPIO_LED, IOPORT_LED, FLASH_PAGE_SIZE): New.
+	* boards/STM8S_DISCOVERY/board.c (USB_Cable_Config, set_led):
+	Remove.
+
+	* regnual/Makefile: Add -I ../src to CFLAGS.
+
+	* regnual/regnual.ld (vector): New.
+
+	* regnual/sys.c: Remove implementation, but jump to vector by sys.h.
+
+	* src/Makefile.in: Follow change of files.
+
+	* src/configure: Undo changes of 2012-05-22.
+
+	* boards/common/hw_config.c: Remove.  Mov function to sys.c.
+	* src/flash.c: Move functions to sys.c.
+	* src/sys.c: New.
+
+	* src/main.c (main): Call flash_mass_erase_and_exec.
+
+	* src/usb_lld.c: Include sys.h.
+
+	* src/usb_lld_sys.c: Remove.  Move interrupt handler to...
+	* src/usb_ctrl.c: ... this file.
+
 	* regnual/sys.c (clock_init, gpio_init, flash_unlock): Removed.
 	(entry): Rename (was: reset).
 
diff --git a/boards/STM8S_DISCOVERY/board.c b/boards/STM8S_DISCOVERY/board.c
index 355efc9..554b598 100644
--- a/boards/STM8S_DISCOVERY/board.c
+++ b/boards/STM8S_DISCOVERY/board.c
@@ -46,22 +46,6 @@ hwinit1 (void)
   AFIO->MAPR |= AFIO_MAPR_TIM3_REMAP_PARTIALREMAP;
 }
 
-void
-USB_Cable_Config (FunctionalState NewState)
-{
-  /* No functionality to stop USB.  */
-  (void)NewState;
-}
-
-void
-set_led (int value)
-{
-  if (value)
-    palSetPad (IOPORT1, GPIOA_LED);
-  else
-    palClearPad (IOPORT1, GPIOA_LED);
-}
-
 #if defined(PINPAD_CIR_SUPPORT)
 void
 cir_ext_disable (void)
diff --git a/boards/STM8S_DISCOVERY/board.h b/boards/STM8S_DISCOVERY/board.h
index 71ad5f2..a9cb272 100644
--- a/boards/STM8S_DISCOVERY/board.h
+++ b/boards/STM8S_DISCOVERY/board.h
@@ -32,6 +32,12 @@
  * Setup for the ST-Link part of STM8S-Discovery board.
  */
 
+#undef	SET_USB_CONDITION		/* No functionality to disconnect USB */
+#define	SET_LED_CONDITION(on) on	/* To emit light, call palSetPad */
+#define GPIO_LED	GPIOA_LED
+#define IOPORT_LED	GPIOA
+#define FLASH_PAGE_SIZE 1024
+
 /*
  * Board identifier.
  */
diff --git a/boards/common/hw_config.c b/boards/common/hw_config.c
deleted file mode 100644
index 0a59997..0000000
--- a/boards/common/hw_config.c
+++ /dev/null
@@ -1,14 +0,0 @@
-/* Hardware specific function */
-
-#include "ch.h"
-#include "hal.h"
-#include "board.h"
-
-const uint8_t *
-unique_device_id (void)
-{
-  /* STM32F103 has 96-bit unique device identifier */
-  const uint8_t *addr = (const uint8_t *)0x1ffff7e8;
-
-  return addr;
-}
diff --git a/regnual/Makefile b/regnual/Makefile
index a6cad6f..991fad4 100644
--- a/regnual/Makefile
+++ b/regnual/Makefile
@@ -23,7 +23,7 @@ MCFLAGS= -mcpu=$(MCU) -mfix-cortex-m3-ldrd
 DEFS = -DFREE_STANDING
 
 CFLAGS = -O2 -g
-CFLAGS += $(CWARN) -fno-common $(MCFLAGS) $(TOPT) $(DEFS)
+CFLAGS += $(CWARN) -I ../src -fno-common $(MCFLAGS) $(TOPT) $(DEFS)
 
 LDFLAGS = -T$(LDSCRIPT) -nostartfiles $(MCFLAGS) $(TOPT)
 
diff --git a/regnual/regnual.c b/regnual/regnual.c
index 8fcca88..1b761da 100644
--- a/regnual/regnual.c
+++ b/regnual/regnual.c
@@ -27,6 +27,7 @@
 
 #include "types.h"
 #include "usb_lld.h"
+#include "sys.h"
 
 extern void *memset (void *s, int c, size_t n);
 
diff --git a/regnual/regnual.ld b/regnual/regnual.ld
index c2f2df4..8b7313e 100644
--- a/regnual/regnual.ld
+++ b/regnual/regnual.ld
@@ -11,6 +11,7 @@ MEMORY
     ram1 : org = 0x20001400, len = 20k - 0x1400
 }
 
+vector = 0x08000000;
 _flash_start = 0x08000000;
 _flash_end   = 0x08020000;
 
diff --git a/regnual/sys-stbee.h b/regnual/sys-stbee.h
deleted file mode 100644
index e164790..0000000
--- a/regnual/sys-stbee.h
+++ /dev/null
@@ -1,16 +0,0 @@
-/*
- * system settings.
- */
-#define STM32_PLLXTPRE			STM32_PLLXTPRE_DIV1
-#define STM32_PLLMUL_VALUE		6
-#define STM32_HSECLK			12000000
-
-#define GPIO_USB_CLEAR_TO_ENABLE       3
-#define GPIO_LED_CLEAR_TO_EMIT         4
-
-#define VAL_GPIO_ODR            0xFFFFFFFF
-#define VAL_GPIO_CRH            0x88888888      /* PD15...PD8 */
-#define VAL_GPIO_CRL            0x88862888      /*  PD7...PD0 */
-
-#define GPIO_USB_BASE	GPIOD_BASE
-#define GPIO_LED_BASE	GPIOD_BASE
diff --git a/regnual/sys-stm8s-discovery.h b/regnual/sys-stm8s-discovery.h
deleted file mode 100644
index d9d6933..0000000
--- a/regnual/sys-stm8s-discovery.h
+++ /dev/null
@@ -1,13 +0,0 @@
-#define STM32_PLLXTPRE			STM32_PLLXTPRE_DIV1
-#define STM32_PLLMUL_VALUE		9
-#define STM32_HSECLK			8000000
-
-#undef  GPIO_USB_CLEAR_TO_ENABLE
-#define GPIO_LED_SET_TO_EMIT		8
-
-#define VAL_GPIO_ODR            0xFFFFFFFF
-#define VAL_GPIO_CRH            0x88888883      /* PD15...PD8 */
-#define VAL_GPIO_CRL            0x88888888      /*  PD7...PD0 */
-
-#define GPIO_LED_BASE	GPIOA_BASE
-#undef  GPIO_USB_BASE
diff --git a/regnual/sys.c b/regnual/sys.c
index ff92e23..fc8d0a9 100644
--- a/regnual/sys.c
+++ b/regnual/sys.c
@@ -1,240 +1,4 @@
 #include "types.h"
-#include "sys.h"
-
-#define STM32_SW_PLL		(2 << 0)
-#define STM32_PLLSRC_HSE	(1 << 16)
-
-#define STM32_PLLXTPRE_DIV1	(0 << 17)
-#define STM32_PLLXTPRE_DIV2	(1 << 17)
-
-#define STM32_HPRE_DIV1		(0 << 4)
-
-#define STM32_PPRE1_DIV2	(4 << 8)
-
-#define STM32_PPRE2_DIV2	(4 << 11)
-
-#define STM32_ADCPRE_DIV4	(1 << 14)
-
-#define STM32_MCO_NOCLOCK	(0 << 24)
-
-#define STM32_SW		STM32_SW_PLL
-#define STM32_PLLSRC		STM32_PLLSRC_HSE
-#define STM32_HPRE		STM32_HPRE_DIV1
-#define STM32_PPRE1		STM32_PPRE1_DIV2
-#define STM32_PPRE2		STM32_PPRE2_DIV2
-#define STM32_ADCPRE		STM32_ADCPRE_DIV4
-#define STM32_MCO		STM32_MCO_NOCLOCK
-
-#define STM32_PLLCLKIN		(STM32_HSECLK / 1)
-#define STM32_PLLMUL		((STM32_PLLMUL_VALUE - 2) << 18)
-#define STM32_PLLCLKOUT		(STM32_PLLCLKIN * STM32_PLLMUL_VALUE)
-#define STM32_SYSCLK		STM32_PLLCLKOUT
-#define STM32_HCLK		(STM32_SYSCLK / 1)
-
-#define STM32_FLASHBITS		0x00000012
-
-struct NVIC {
-  uint32_t ISER[8];
-  uint32_t unused1[24];
-  uint32_t ICER[8];
-  uint32_t unused2[24];
-  uint32_t ISPR[8];
-  uint32_t unused3[24];
-  uint32_t ICPR[8];
-  uint32_t unused4[24];
-  uint32_t IABR[8];
-  uint32_t unused5[56];
-  uint32_t IPR[60];
-};
-
-#define NVICBase	((struct NVIC *)0xE000E100)
-#define NVIC_ISER(n)	(NVICBase->ISER[n])
-#define NVIC_ICPR(n)	(NVICBase->ICPR[n])
-#define NVIC_IPR(n)	(NVICBase->IPR[n])
-
-static void NVICEnableVector (uint32_t n, uint32_t prio)
-{
-  unsigned int sh = (n & 3) << 3;
-
-  NVIC_IPR (n >> 2) = (NVIC_IPR(n >> 2) & ~(0xFF << sh)) | (prio << sh);
-  NVIC_ICPR (n >> 5) = 1 << (n & 0x1F);
-  NVIC_ISER (n >> 5) = 1 << (n & 0x1F);
-}
-
-
-#define PERIPH_BASE	0x40000000
-#define APB2PERIPH_BASE	(PERIPH_BASE + 0x10000)
-#define AHBPERIPH_BASE	(PERIPH_BASE + 0x20000)
-
-struct RCC {
-  __IO uint32_t CR;
-  __IO uint32_t CFGR;
-  __IO uint32_t CIR;
-  __IO uint32_t APB2RSTR;
-  __IO uint32_t APB1RSTR;
-  __IO uint32_t AHBENR;
-  __IO uint32_t APB2ENR;
-  __IO uint32_t APB1ENR;
-  __IO uint32_t BDCR;
-  __IO uint32_t CSR;
-};
-
-#define RCC_BASE		(AHBPERIPH_BASE + 0x1000)
-#define RCC			((struct RCC *)RCC_BASE)
-
-#define RCC_APB1ENR_USBEN	0x00800000
-#define RCC_APB1RSTR_USBRST	0x00800000
-
-#define RCC_CR_HSION		0x00000001
-#define RCC_CR_HSIRDY		0x00000002
-#define RCC_CR_HSITRIM		0x000000F8
-#define RCC_CR_HSEON		0x00010000
-#define RCC_CR_HSERDY		0x00020000
-#define RCC_CR_PLLON		0x01000000
-#define RCC_CR_PLLRDY		0x02000000
-
-#define RCC_CFGR_SWS		0x0000000C
-#define RCC_CFGR_SWS_HSI	0x00000000
-
-struct FLASH {
-  __IO uint32_t ACR;
-  __IO uint32_t KEYR;
-  __IO uint32_t OPTKEYR;
-  __IO uint32_t SR;
-  __IO uint32_t CR;
-  __IO uint32_t AR;
-  __IO uint32_t RESERVED;
-  __IO uint32_t OBR;
-  __IO uint32_t WRPR;
-};
-
-#define FLASH_R_BASE	(AHBPERIPH_BASE + 0x2000)
-#define FLASH		((struct FLASH *) FLASH_R_BASE)
-
-
-#define RCC_APB2ENR_IOPAEN	0x00000004
-#define RCC_APB2RSTR_IOPARST	0x00000004
-#define RCC_APB2ENR_IOPDEN	0x00000020
-#define RCC_APB2RSTR_IOPDRST	0x00000020
-
-#define VAL_GPIOAODR            0xFFFFFFFF
-#define VAL_GPIOACRH            0x88888888      /* PA15...PA8 */
-#define VAL_GPIOACRL            0x88888884      /*  PA7...PA0 */
-
-struct GPIO {
-  __IO uint32_t CRL;
-  __IO uint32_t CRH;
-  __IO uint32_t IDR;
-  __IO uint32_t ODR;
-  __IO uint32_t BSRR;
-  __IO uint32_t BRR;
-  __IO uint32_t LCKR;
-};
-
-#define GPIOA_BASE	(APB2PERIPH_BASE + 0x0800)
-#define GPIOA		((struct GPIO *) GPIOA_BASE)
-#define GPIOB_BASE	(APB2PERIPH_BASE + 0x0C00)
-#define GPIOB		((struct GPIO *) GPIOB_BASE)
-#define GPIOC_BASE	(APB2PERIPH_BASE + 0x1000)
-#define GPIOC		((struct GPIO *) GPIOC_BASE)
-#define GPIOD_BASE	(APB2PERIPH_BASE + 0x1400)
-#define GPIOD		((struct GPIO *) GPIOD_BASE)
-#define GPIOE_BASE	(APB2PERIPH_BASE + 0x1800)
-#define GPIOE		((struct GPIO *) GPIOE_BASE)
-
-#ifdef GPIO_USB_BASE
-#define GPIO_USB	((struct GPIO *) GPIO_USB_BASE)
-#endif
-#define GPIO_LED	((struct GPIO *) GPIO_LED_BASE)
-
-static void
-usb_cable_config (int on)
-{
-#ifdef GPIO_USB_BASE
-# ifdef GPIO_USB_CLEAR_TO_ENABLE
-  if (on)
-    GPIO_USB->BRR = (1 << GPIO_USB_CLEAR_TO_ENABLE);
-  else
-    GPIO_USB->BSRR = (1 << GPIO_USB_CLEAR_TO_ENABLE);
-# endif
-# ifdef GPIO_USB_SET_TO_ENABLE
-  if (on)
-    GPIO_USB->BSRR = (1 << GPIO_USB_SET_TO_ENABLE);
-  else
-    GPIO_USB->BRR = (1 << GPIO_USB_SET_TO_ENABLE);
-# endif
-#else
-  (void)on;
-#endif
-}
-
-void
-set_led (int on)
-{
-#ifdef GPIO_LED_CLEAR_TO_EMIT
-  if (on)
-    GPIO_LED->BRR = (1 << GPIO_LED_CLEAR_TO_EMIT);
-  else
-    GPIO_LED->BSRR = (1 << GPIO_LED_CLEAR_TO_EMIT);
-#endif
-#ifdef GPIO_LED_SET_TO_EMIT
-  if (on)
-    GPIO_LED->BSRR = (1 << GPIO_LED_SET_TO_EMIT);
-  else
-    GPIO_LED->BRR = (1 << GPIO_LED_SET_TO_EMIT);
-#endif
-}
-
-
-#define USB_IRQ 20
-#define USB_IRQ_PRIORITY ((11) << 4)
-
-void usb_lld_sys_init (void)
-{
-  RCC->APB1ENR |= RCC_APB1ENR_USBEN;
-  NVICEnableVector (USB_IRQ, USB_IRQ_PRIORITY);
-  RCC->APB1RSTR = RCC_APB1RSTR_USBRST;
-  RCC->APB1RSTR = 0;
-  usb_cable_config (1);
-}
-
-void usb_lld_sys_shutdown (void)
-{
-  RCC->APB1ENR &= ~RCC_APB1ENR_USBEN;
-}
-
-
-#define FLASH_KEY1               0x45670123UL
-#define FLASH_KEY2               0xCDEF89ABUL
-
-enum flash_status
-{
-  FLASH_BUSY = 1,
-  FLASH_ERROR_PG,
-  FLASH_ERROR_WRP,
-  FLASH_COMPLETE,
-  FLASH_TIMEOUT
-};
-
-#define FLASH_SR_BSY		0x01
-#define FLASH_SR_PGERR		0x04
-#define FLASH_SR_WRPRTERR	0x10
-#define FLASH_SR_EOP		0x20
-
-#define FLASH_CR_PG	0x0001
-#define FLASH_CR_PER	0x0002
-#define FLASH_CR_MER	0x0004
-#define FLASH_CR_OPTPG	0x0010
-#define FLASH_CR_OPTER	0x0020
-#define FLASH_CR_STRT	0x0040
-#define FLASH_CR_LOCK	0x0080
-#define FLASH_CR_OPTWRE	0x0200
-#define FLASH_CR_ERRIE	0x0400
-#define FLASH_CR_EOPIE	0x1000
-
-#define FLASH_OBR_RDPRT 0x00000002
-
-#define OPTION_BYTES_ADDR 0x1ffff800
 
 static void fatal (void)
 {
@@ -249,9 +13,7 @@ static void none (void)
 static __attribute__ ((naked))
 void entry (void)
 {
-  asm volatile ("cpsid	i\n\t"	/* Mask all interrupts */
-		"ldr	r0, =__ram_end__\n\t"
-		"msr	MSP, r0\n\t" /* Main (interrupt handler) stack */
+  asm volatile ("ldr	r0, =__ram_end__\n\t"
 		"ldr	r1, =__main_stack_size__\n\t"
 		"subs	r0, r0, r1\n\t"
 		"msr	PSP, r0\n\t" /* Process (main routine) stack */
@@ -278,11 +40,6 @@ void entry (void)
 		: /* no output */ : /* no input */ : "memory");
 }
 
-#define intr_disable()  asm volatile ("cpsid   i" : : "r" (0) : "memory")
-
-#define intr_enable()  asm volatile ("msr     BASEPRI, %0\n\t"		 \
-				     "cpsie   i" : : "r" (0) : "memory")
-
 typedef void (*handler)(void);
 extern uint8_t __ram_end__;
 extern void usb_interrupt_handler (void);
@@ -308,144 +65,3 @@ handler vector_table[] __attribute__ ((section(".vectors"))) = {
   /* 90 */
   usb_interrupt_handler,
 };
-
-static int
-flash_get_status (void)
-{
-  int status;
-
-  if ((FLASH->SR & FLASH_SR_BSY) != 0)
-    status = FLASH_BUSY;
-  else if ((FLASH->SR & FLASH_SR_PGERR) != 0)
-    status = FLASH_ERROR_PG;
-  else if((FLASH->SR & FLASH_SR_WRPRTERR) != 0 )
-    status = FLASH_ERROR_WRP;
-  else
-    status = FLASH_COMPLETE;
-
-  return status;
-}
-
-static int
-flash_wait_for_last_operation (uint32_t timeout)
-{
-  int status;
-
-  do
-    if (--timeout == 0)
-      return FLASH_TIMEOUT;
-    else
-      status = flash_get_status ();
-  while (status == FLASH_BUSY);
-
-  return status;
-}
-
-#define FLASH_PROGRAM_TIMEOUT 0x00010000
-#define FLASH_ERASE_TIMEOUT   0x01000000
-
-static int
-flash_program_halfword (uint32_t addr, uint16_t data)
-{
-  int status;
-
-  status = flash_wait_for_last_operation (FLASH_PROGRAM_TIMEOUT);
-
-  intr_disable ();
-  if (status == FLASH_COMPLETE)
-    {
-      FLASH->CR |= FLASH_CR_PG;
-
-      *(volatile uint16_t *)addr = data;
-
-      status = flash_wait_for_last_operation (FLASH_PROGRAM_TIMEOUT);
-      FLASH->CR &= ~FLASH_CR_PG;
-    }
-  intr_enable ();
-
-  return status;
-}
-
-int
-flash_write (uint32_t dst_addr, const uint8_t *src, size_t len)
-{
-  int status;
-
-  while (len)
-    {
-      uint16_t hw = *src++;
-
-      hw |= (*src++ << 8);
-      status = flash_program_halfword (dst_addr, hw);
-      if (status != FLASH_COMPLETE)
-	return 0;		/* error return */
-
-      dst_addr += 2;
-      len -= 2;
-    }
-
-  return 1;
-}
-
-int
-flash_protect (void)
-{
-  int status;
-  uint32_t option_bytes_value;
-
-  status = flash_wait_for_last_operation (FLASH_ERASE_TIMEOUT);
-
-  intr_disable ();
-  if (status == FLASH_COMPLETE)
-    {
-      FLASH->OPTKEYR = FLASH_KEY1;
-      FLASH->OPTKEYR = FLASH_KEY2;
-
-      FLASH->CR |= FLASH_CR_OPTER;
-      FLASH->CR |= FLASH_CR_STRT;
-
-      status = flash_wait_for_last_operation (FLASH_ERASE_TIMEOUT);
-      FLASH->CR &= ~FLASH_CR_OPTER;
-    }
-  intr_enable ();
-
-  if (status != FLASH_COMPLETE)
-    return 0;
-
-  option_bytes_value = *(uint32_t *)OPTION_BYTES_ADDR;
-  return (option_bytes_value & 0xff) == 0xff ? 1 : 0;
-}
-
-struct SCB
-{
-  __IO uint32_t CPUID;
-  __IO uint32_t ICSR;
-  __IO uint32_t VTOR;
-  __IO uint32_t AIRCR;
-  __IO uint32_t SCR;
-  __IO uint32_t CCR;
-  __IO uint8_t  SHP[12];
-  __IO uint32_t SHCSR;
-  __IO uint32_t CFSR;
-  __IO uint32_t HFSR;
-  __IO uint32_t DFSR;
-  __IO uint32_t MMFAR;
-  __IO uint32_t BFAR;
-  __IO uint32_t AFSR;
-  __IO uint32_t PFR[2];
-  __IO uint32_t DFR;
-  __IO uint32_t ADR;
-  __IO uint32_t MMFR[4];
-  __IO uint32_t ISAR[5];
-};
-
-#define SCS_BASE	(0xE000E000)
-#define SCB_BASE	(SCS_BASE +  0x0D00)
-#define SCB		((struct SCB *) SCB_BASE)
-
-#define SYSRESETREQ 0x04
-void nvic_system_reset (void)
-{
-  SCB->AIRCR = (0x05FA0000 | (SCB->AIRCR & 0x70) | SYSRESETREQ);
-  asm volatile ("dsb");
-}
diff --git a/src/Makefile.in b/src/Makefile.in
index 4130b46..d896426 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -76,15 +76,14 @@ CSRC = $(PORTSRC) \
        $(HALSRC) \
        $(PLATFORMSRC) \
        $(BOARDSRC) \
-       ../boards/common/hw_config.c \
        $(BOARD_DIR)/board.c \
        $(CHIBIOS)/os/various/evtimer.c \
        $(CHIBIOS)/os/various/syscalls.c \
        $(CRYPTSRC) \
-       main.c usb_lld.c usb_lld_sys.c \
+       main.c usb_lld.c \
 	usb_desc.c usb_ctrl.c \
 	usb-icc.c openpgp.c ac.c openpgp-do.c flash.c \
-	random.c neug.c
+	random.c neug.c sys.c
 
 ifneq ($(ENABLE_DEBUG),)
 CSRC += debug.c
diff --git a/src/configure b/src/configure
index 28e45b8..25ddd0e 100755
--- a/src/configure
+++ b/src/configure
@@ -135,7 +135,6 @@ fi
 BOARD_DIR=../boards/$target
 if test -d $BOARD_DIR; then
   echo "Configured for target: $target"
-  TARGET_LOWER=`echo $target | tr '[:upper:]_' '[:lower:]-'`
 else
   echo "Unsupported target \`$target'" >&2
   exit 1
@@ -219,8 +218,6 @@ else
   echo "CERT.3 Data Object is not supported"
 fi
 
-ln -sf sys-$TARGET_LOWER.h ../regnual/sys.h
-
 sed -e "s%@BOARD_DIR@%$BOARD_DIR%" \
     -e "s%@DEBUG_MAKE_OPTION@%$DEBUG_MAKE_OPTION%" \
     -e "s%@PINPAD_MAKE_OPTION@%$PINPAD_MAKE_OPTION%" \
diff --git a/src/flash.c b/src/flash.c
index 4f4bc07..76b98a2 100644
--- a/src/flash.c
+++ b/src/flash.c
@@ -32,108 +32,9 @@
 #include "config.h"
 #include "ch.h"
 #include "hal.h"
+#include "sys.h"
 #include "gnuk.h"
 
-#define FLASH_KEY1               0x45670123UL
-#define FLASH_KEY2               0xCDEF89ABUL
-
-enum flash_status
-{
-  FLASH_BUSY = 1,
-  FLASH_ERROR_PG,
-  FLASH_ERROR_WRP,
-  FLASH_COMPLETE,
-  FLASH_TIMEOUT
-};
-
-void
-flash_unlock (void)
-{
-  FLASH->KEYR = FLASH_KEY1;
-  FLASH->KEYR = FLASH_KEY2;
-}
-
-static int
-flash_get_status (void)
-{
-  int status;
-
-  if ((FLASH->SR & FLASH_SR_BSY) != 0)
-    status = FLASH_BUSY;
-  else if ((FLASH->SR & FLASH_SR_PGERR) != 0)
-    status = FLASH_ERROR_PG;
-  else if((FLASH->SR & FLASH_SR_WRPRTERR) != 0)
-    status = FLASH_ERROR_WRP;
-  else
-    status = FLASH_COMPLETE;
-
-  return status;
-}
-
-static int
-flash_wait_for_last_operation (uint32_t timeout)
-{
-  int status;
-
-  do
-    if (--timeout == 0)
-      return FLASH_TIMEOUT;
-    else
-      status = flash_get_status ();
-  while (status == FLASH_BUSY);
-
-  return status;
-}
-
-#define FLASH_PROGRAM_TIMEOUT 0x00010000
-#define FLASH_ERASE_TIMEOUT   0x01000000
-
-static int
-flash_program_halfword (uint32_t addr, uint16_t data)
-{
-  int status;
-
-  status = flash_wait_for_last_operation (FLASH_PROGRAM_TIMEOUT);
-
-  chSysLock ();
-  if (status == FLASH_COMPLETE)
-    {
-      FLASH->CR |= FLASH_CR_PG;
-
-      *(volatile uint16_t *)addr = data;
-
-      status = flash_wait_for_last_operation (FLASH_PROGRAM_TIMEOUT);
-      if (status != FLASH_TIMEOUT)
-	FLASH->CR &= ~FLASH_CR_PG;
-    }
-  chSysUnlock ();
-
-  return status;
-}
-
-static int
-flash_erase_page (uint32_t addr)
-{
-  int status;
-
-  status = flash_wait_for_last_operation (FLASH_ERASE_TIMEOUT);
-
-  chSysLock ();
-  if (status == FLASH_COMPLETE)
-    {
-      FLASH->CR |= FLASH_CR_PER;
-      FLASH->AR = addr; 
-      FLASH->CR |= FLASH_CR_STRT;
-
-      status = flash_wait_for_last_operation (FLASH_ERASE_TIMEOUT);
-      if (status != FLASH_TIMEOUT)
-	FLASH->CR &= ~FLASH_CR_PER;
-    }
-  chSysUnlock ()
-
-  return status;
-}
-
 /*
  * Flash memory map
  *
@@ -294,14 +195,14 @@ flash_do_write_internal (const uint8_t *p, int nr, const uint8_t *data, int len)
 
   addr = (uint32_t)p;
   hw = nr | (len << 8);
-  if (flash_program_halfword (addr, hw) != FLASH_COMPLETE)
+  if (flash_program_halfword (addr, hw) != 0)
     flash_warning ("DO WRITE ERROR");
   addr += 2;
 
   for (i = 0; i < len/2; i++)
     {
       hw = data[i*2] | (data[i*2+1]<<8);
-      if (flash_program_halfword (addr, hw) != FLASH_COMPLETE)
+      if (flash_program_halfword (addr, hw) != 0)
 	flash_warning ("DO WRITE ERROR");
       addr += 2;
     }
@@ -309,7 +210,7 @@ flash_do_write_internal (const uint8_t *p, int nr, const uint8_t *data, int len)
   if ((len & 1))
     {
       hw = data[i*2] | 0xff00;
-      if (flash_program_halfword (addr, hw) != FLASH_COMPLETE)
+      if (flash_program_halfword (addr, hw) != 0)
 	flash_warning ("DO WRITE ERROR");
     }
 }
@@ -359,19 +260,19 @@ flash_do_release (const uint8_t *do_data)
   /* Fill zero for content and pad */
   for (i = 0; i < len/2; i ++)
     {
-      if (flash_program_halfword (addr, 0) != FLASH_COMPLETE)
+      if (flash_program_halfword (addr, 0) != 0)
 	flash_warning ("fill-zero failure");
       addr += 2;
     }
 
   if ((len & 1))
     {
-      if (flash_program_halfword (addr, 0) != FLASH_COMPLETE)
+      if (flash_program_halfword (addr, 0) != 0)
 	flash_warning ("fill-zero pad failure");
     }
 
   /* Fill 0x0000 for "tag_number and length" word */
-  if (flash_program_halfword (addr_tag, 0) != FLASH_COMPLETE)
+  if (flash_program_halfword (addr_tag, 0) != 0)
     flash_warning ("fill-zero tag_nr failure");
 }
 
@@ -399,7 +300,7 @@ flash_key_write (uint8_t *key_addr, const uint8_t *key_data,
   for (i = 0; i < KEY_CONTENT_LEN/2; i ++)
     {
       hw = key_data[i*2] | (key_data[i*2+1]<<8);
-      if (flash_program_halfword (addr, hw) != FLASH_COMPLETE)
+      if (flash_program_halfword (addr, hw) != 0)
 	return -1;
       addr += 2;
     }
@@ -407,7 +308,7 @@ flash_key_write (uint8_t *key_addr, const uint8_t *key_data,
   for (i = 0; i < KEY_CONTENT_LEN/2; i ++)
     {
       hw = modulus[i*2] | (modulus[i*2+1]<<8);
-      if (flash_program_halfword (addr, hw) != FLASH_COMPLETE)
+      if (flash_program_halfword (addr, hw) != 0)
 	return -1;
       addr += 2;
     }
@@ -579,18 +480,6 @@ flash_cnt123_clear (const uint8_t **addr_p)
 }
 
 
-static int
-flash_check_blank (const uint8_t *p_start, int size)
-{
-  const uint8_t *p;
-
-  for (p = p_start; p < p_start + size; p++)
-    if (*p != 0xff)
-      return 0;
-
-  return 1;
-}
-
 #if defined(CERTDO_SUPPORT)
 #define FLASH_CH_CERTIFICATE_SIZE 2048
 int
@@ -652,7 +541,7 @@ flash_write_binary (uint8_t file_id, const uint8_t *data,
       for (i = 0; i < len/2; i++)
 	{
 	  hw = data[i*2] | (data[i*2+1]<<8);
-	  if (flash_program_halfword (addr, hw) != FLASH_COMPLETE)
+	  if (flash_program_halfword (addr, hw) != 0)
 	    flash_warning ("DO WRITE ERROR");
 	  addr += 2;
 	}
diff --git a/src/gnuk.h b/src/gnuk.h
index 5972d3d..36b333f 100644
--- a/src/gnuk.h
+++ b/src/gnuk.h
@@ -129,7 +129,6 @@ enum kind_of_key {
   GPG_KEY_FOR_AUTHENTICATION,
 };
 
-extern void flash_unlock (void);
 extern const uint8_t *flash_init (void);
 extern void flash_do_release (const uint8_t *);
 extern const uint8_t *flash_do_write (uint8_t nr, const uint8_t *data, int len);
@@ -322,8 +321,6 @@ extern uint32_t get_salt (void);
 
 extern uint32_t hardclock (void);
 
-extern void set_led (int);
-
 #define NUM_ALL_PRV_KEYS 3	/* SIG, DEC and AUT */
 
 extern uint8_t pw1_keystring[KEYSTRING_SIZE_PW1];
@@ -351,7 +348,6 @@ extern void flash_bool_write_internal (const uint8_t *p, int nr);
 extern void flash_cnt123_write_internal (const uint8_t *p, int which, int v);
 extern void flash_do_write_internal (const uint8_t *p, int nr, const uint8_t *data, int len);
 
-extern const unsigned char *unique_device_id (void);
 extern const uint8_t gnukStringSerial[];
 
 #define LED_ONESHOT_SHORT ((eventmask_t)1)
diff --git a/src/main.c b/src/main.c
index 135a9d4..2df00c4 100644
--- a/src/main.c
+++ b/src/main.c
@@ -24,6 +24,7 @@
 #include "config.h"
 #include "ch.h"
 #include "hal.h"
+#include "sys.h"
 #include "gnuk.h"
 #include "usb_lld.h"
 #include "usb-cdc.h"
@@ -370,55 +371,6 @@ led_blink (int spec)
 }
 
 
-#define FMEAE_SIZE 128
-
-#define FLASH_MASS_ERASE_TIMEOUT   0xF0000000
-
-static void __attribute__((naked))
-flash_mass_erase_and_exec (void)
-{
-  void (**func )(void) = (void (**)(void))(&_regnual_start + 4);
-
-  if ((FLASH->SR & FLASH_SR_BSY) == 0)
-    {
-      FLASH->CR |= FLASH_CR_MER;
-      FLASH->CR |= FLASH_CR_STRT;
-
-      while ((FLASH->SR & FLASH_SR_BSY) != 0)
-	;
-
-      FLASH->CR &= ~FLASH_CR_MER;
-
-      if ((FLASH->SR & (FLASH_SR_BSY|FLASH_SR_PGERR|FLASH_SR_WRPRTERR)) == 0)
-	(**func) ();
-    }
-
-  for (;;);
-}
-
-static void __attribute__((noreturn))
-good_bye (void)
-{
-  register uint32_t dst __asm__ ("r0") = 0x20000000; /* SRAM top */
-  register uint32_t src __asm__ ("r1") = (uint32_t)flash_mass_erase_and_exec & ~1;
-  register uint32_t len __asm__ ("r2") = FMEAE_SIZE;
-  register uint32_t entry __asm__ ("r3") = dst | 1;
-  register uint32_t use __asm__ ("r4");
-
-  /* copy function flash_mass_erase_and_exec to SRAM and jump to it */
-  asm volatile("add	r2, r2, r1\n"
-	"0:	ldr	r4, [r1], #4\n\t"
-	       "cmp	r2, r1\n\t"
-	       "str	r4, [r0], #4\n\t"
-	       "bhi	0b\n\t"
-	       "isb\n\t"
-	       "bx	r3"
-	       : "=r" (dst), "=r" (src), "=r" (len), "=r" (use)
-	       : "0" (dst), "1" (src), "2" (len), "r" (entry)
-	       : "memory");
-  for (;;);
-}
-
 /*
  * Entry point.
  *
@@ -524,15 +476,12 @@ main (int argc, char *argv[])
     }
 
   set_led (1);
-  /* USB Dissconnect (when supported) */
   usb_lld_shutdown ();
-  USB_Cable_Config (0);
-  chThdSleep (MS2ST (1));	/* > 2.5us required */
   port_disable ();
   /* set vector */
   SCB->VTOR = (uint32_t)&_regnual_start;
   /* leave Gnuk */ 
-  good_bye ();
+  flash_mass_erase_and_exec ();
 
   /* Never reached */
   return 0;
diff --git a/src/openpgp-do.c b/src/openpgp-do.c
index 90de71b..5849f6f 100644
--- a/src/openpgp-do.c
+++ b/src/openpgp-do.c
@@ -25,6 +25,7 @@
 
 #include "config.h"
 #include "ch.h"
+#include "sys.h"
 #include "gnuk.h"
 #include "openpgp.h"
 
diff --git a/src/sys.c b/src/sys.c
new file mode 100644
index 0000000..0c6e7b7
--- /dev/null
+++ b/src/sys.c
@@ -0,0 +1,276 @@
+#include "ch.h"
+#include "hal.h"
+#include "board.h"
+#include "usb_lld.h"
+
+static const uint8_t *
+unique_device_id (void)
+{
+  /* STM32F103 has 96-bit unique device identifier */
+  const uint8_t *addr = (const uint8_t *)0x1ffff7e8;
+
+  return addr;
+}
+
+static void
+usb_cable_config (int enable)
+{
+#if defined(SET_USB_CONDITION)
+  if (SET_USB_CONDITION (enable))
+    palSetPad (IOPORT_USB, GPIO_USB);
+  else
+    palClearPad (IOPORT_USB, GPIO_USB);
+#else
+  (void)enable;
+#endif
+}
+
+static void
+set_led (int on)
+{
+  if (SET_LED_CONDITION (on))
+    palSetPad (IOPORT_LED, GPIO_LED);
+  else
+    palClearPad (IOPORT_LED, GPIO_LED);
+}
+
+
+#define FLASH_KEY1               0x45670123UL
+#define FLASH_KEY2               0xCDEF89ABUL
+
+static void
+flash_unlock (void)
+{
+  FLASH->KEYR = FLASH_KEY1;
+  FLASH->KEYR = FLASH_KEY2;
+}
+
+
+static int
+flash_wait_for_last_operation (uint32_t timeout)
+{
+  int status;
+
+  do
+    {
+      status = FLASH->SR;
+      if (--timeout == 0)
+	break;
+    }
+  while ((status & FLASH_SR_BSY) != 0);
+
+  return status & (FLASH_SR_BSY|FLASH_SR_PGERR|FLASH_SR_WRPRTERR);
+}
+
+#define FLASH_PROGRAM_TIMEOUT 0x00010000
+#define FLASH_ERASE_TIMEOUT   0x01000000
+
+static int
+flash_program_halfword (uint32_t addr, uint16_t data)
+{
+  int status;
+
+  status = flash_wait_for_last_operation (FLASH_PROGRAM_TIMEOUT);
+
+  port_disable ();
+  if (status == 0)
+    {
+      FLASH->CR |= FLASH_CR_PG;
+
+      *(volatile uint16_t *)addr = data;
+
+      status = flash_wait_for_last_operation (FLASH_PROGRAM_TIMEOUT);
+      FLASH->CR &= ~FLASH_CR_PG;
+    }
+  port_enable ();
+
+  return status;
+}
+
+static int
+flash_erase_page (uint32_t addr)
+{
+  int status;
+
+  status = flash_wait_for_last_operation (FLASH_ERASE_TIMEOUT);
+
+  port_disable ();
+  if (status == 0)
+    {
+      FLASH->CR |= FLASH_CR_PER;
+      FLASH->AR = addr; 
+      FLASH->CR |= FLASH_CR_STRT;
+
+      status = flash_wait_for_last_operation (FLASH_ERASE_TIMEOUT);
+      FLASH->CR &= ~FLASH_CR_PER;
+    }
+  port_enable ();
+
+  return status;
+}
+
+static int
+flash_check_blank (const uint8_t *p_start, size_t size)
+{
+  const uint8_t *p;
+
+  for (p = p_start; p < p_start + size; p++)
+    if (*p != 0xff)
+      return 0;
+
+  return 1;
+}
+
+static int
+flash_write (uint32_t dst_addr, const uint8_t *src, size_t len)
+{
+  int status;
+
+  while (len)
+    {
+      uint16_t hw = *src++;
+
+      hw |= (*src++ << 8);
+      status = flash_program_halfword (dst_addr, hw);
+      if (status != 0)
+	return 0;		/* error return */
+
+      dst_addr += 2;
+      len -= 2;
+    }
+
+  return 1;
+}
+
+#define OPTION_BYTES_ADDR 0x1ffff800
+
+static int
+flash_protect (void)
+{
+  int status;
+  uint32_t option_bytes_value;
+
+  status = flash_wait_for_last_operation (FLASH_ERASE_TIMEOUT);
+
+  port_disable ();
+  if (status == 0)
+    {
+      FLASH->OPTKEYR = FLASH_KEY1;
+      FLASH->OPTKEYR = FLASH_KEY2;
+
+      FLASH->CR |= FLASH_CR_OPTER;
+      FLASH->CR |= FLASH_CR_STRT;
+
+      status = flash_wait_for_last_operation (FLASH_ERASE_TIMEOUT);
+      FLASH->CR &= ~FLASH_CR_OPTER;
+    }
+  port_enable ();
+
+  if (status != 0)
+    return 0;
+
+  option_bytes_value = *(uint32_t *)OPTION_BYTES_ADDR;
+  return (option_bytes_value & 0xff) == 0xff ? 1 : 0;
+}
+
+#define FLASH_MASS_ERASE_TIMEOUT   0xF0000000
+
+extern uint8_t __flash_start__, __flash_end__;
+extern uint8_t _regnual_start;
+
+static void __attribute__((naked))
+flash_mass_erase_and_exec (void)
+{
+  void (**func )(void) = (void (**)(void))(&_regnual_start + 4);
+  uint32_t addr = (uint32_t)&__flash_start__;
+  uint32_t end = (uint32_t)&__flash_end__;
+  int r;
+
+  while (addr < end)
+    {
+      r = flash_erase_page (addr);
+      if (r != 0)
+	break;
+
+      addr += FLASH_PAGE_SIZE;
+    }
+
+  if (addr >= end)
+    (**func) ();
+
+  for (;;);
+}
+
+static void
+nvic_enable_vector (uint32_t n, uint32_t prio)
+{
+  unsigned int sh = (n & 3) << 3;
+
+  NVIC_IPR (n >> 2) = (NVIC_IPR(n >> 2) & ~(0xFF << sh)) | (prio << sh);
+  NVIC_ICPR (n >> 5) = 1 << (n & 0x1F);
+  NVIC_ISER (n >> 5) = 1 << (n & 0x1F);
+}
+
+static void
+usb_lld_sys_init (void)
+{
+  RCC->APB1ENR |= RCC_APB1ENR_USBEN;
+  nvic_enable_vector (USB_LP_CAN1_RX0_IRQn,
+		      CORTEX_PRIORITY_MASK (STM32_USB_IRQ_PRIORITY));
+  /*
+   * Note that we also have other IRQ(s):
+   * 	USB_HP_CAN1_TX_IRQn (for double-buffered or isochronous)
+   * 	USBWakeUp_IRQn (suspend/resume)
+   */
+  RCC->APB1RSTR = RCC_APB1RSTR_USBRST;
+  RCC->APB1RSTR = 0;
+
+  usb_cable_config (1);
+}
+
+static void
+usb_lld_sys_shutdown (void)
+{
+  RCC->APB1ENR &= ~RCC_APB1ENR_USBEN;
+  usb_cable_config (0);
+}
+
+#define SYSRESETREQ 0x04
+static void
+nvic_system_reset (void)
+{
+  SCB->AIRCR = (0x05FA0000 | (SCB->AIRCR & 0x70) | SYSRESETREQ);
+  asm volatile ("dsb");
+}
+
+static void __attribute__ ((naked))
+reset (void)
+{
+  asm volatile ("cpsid	i\n\t"		/* Mask all interrupts            */
+		"ldr	r0, =_text\n\t"
+		"ldr	r1, [r0], #4\n\t"
+		"msr	MSP, r1\n\t"	/* Main (exception handler) stack */
+		"ldr	r1, [r0]\n\t"	/* Reset handler                  */
+		"bx	r1\n"
+		: /* no output */ : /* no input */ : "memory");
+}
+
+typedef void (*handler)(void);
+extern uint8_t __ram_end__;
+
+handler vector[] __attribute__ ((section(".vectors"))) = {
+  (handler)&__ram_end__,
+  reset,
+  (handler)unique_device_id,
+  (handler)set_led,
+  flash_unlock,
+  (handler)flash_program_halfword,
+  (handler)flash_erase_page,
+  (handler)flash_check_blank,
+  (handler)flash_write,
+  (handler)flash_protect,
+  (handler)flash_mass_erase_and_exec,
+  usb_lld_sys_init,
+  usb_lld_sys_shutdown,
+  nvic_system_reset,
+};
diff --git a/src/sys.h b/src/sys.h
new file mode 100644
index 0000000..18b6b3f
--- /dev/null
+++ b/src/sys.h
@@ -0,0 +1,92 @@
+typedef void (*handler)(void);
+extern handler vector[12];
+
+static inline const uint8_t *
+unique_device_id (void)
+{
+  const uint8_t * (*func) (void) = (const uint8_t * (*)(void))vector[0];
+
+  return (*func) ();
+}
+
+static inline void
+set_led (int on)
+{
+  void (*func) (int) = (void (*)(int))vector[1];
+
+  return (*func) (on);
+}
+
+static inline void
+flash_unlock (void)
+{
+  (*vector[2]) ();
+}
+
+static inline int
+flash_program_halfword (uint32_t addr, uint16_t data)
+{
+  int (*func) (uint32_t, uint16_t) = (int (*)(uint32_t, uint16_t))vector[3];
+
+  return (*func) (addr, data);
+}
+
+static inline int
+flash_erase_page (uint32_t addr)
+{
+  int (*func) (uint32_t) = (int (*)(uint32_t))vector[4];
+
+  return (*func) (addr);
+}
+
+static inline int
+flash_check_blank (const uint8_t *p_start, size_t size)
+{
+  int (*func) (const uint8_t *, int) = (int (*)(const uint8_t *, int))vector[5];
+
+  return (*func) (p_start, size);
+}
+
+static inline int
+flash_write (uint32_t dst_addr, const uint8_t *src, size_t len)
+{
+  int (*func) (uint32_t, const uint8_t *, size_t)
+    = (int (*)(uint32_t, const uint8_t *, size_t))vector[6];
+
+  return (*func) (dst_addr, src, len);
+}
+
+static inline int
+flash_protect (void)
+{
+  int (*func) (void) = (int (*)(void))vector[7];
+
+  return (*func) ();
+}
+
+static inline void __attribute__((noreturn))
+flash_mass_erase_and_exec (void)
+{
+  void (*func) (void) = (void (*)(void))vector[8];
+
+  (*func) ();
+  for (;;);
+}
+
+static inline void
+usb_lld_sys_init (void)
+{
+  (*vector[9]) ();
+}
+
+static inline void
+usb_lld_sys_shutdown (void)
+{
+  (*vector[10]) ();
+}
+
+static inline void
+nvic_system_reset (void)
+{
+  (*vector[11]) ();
+}
diff --git a/src/usb_ctrl.c b/src/usb_ctrl.c
index da116d0..c7ee886 100644
--- a/src/usb_ctrl.c
+++ b/src/usb_ctrl.c
@@ -423,3 +423,14 @@ const struct usb_device_method Device_Method = {
   gnuk_usb_event,
   gnuk_interface,
 };
+
+CH_IRQ_HANDLER (Vector90)
+{
+  CH_IRQ_PROLOGUE();
+  chSysLockFromIsr();
+
+  usb_interrupt_handler ();
+
+  chSysUnlockFromIsr();
+  CH_IRQ_EPILOGUE();
+}
diff --git a/src/usb_lld.c b/src/usb_lld.c
index 5fc9bac..1c31a04 100644
--- a/src/usb_lld.c
+++ b/src/usb_lld.c
@@ -4,7 +4,7 @@
 #include "ch.h"
 #include "hal.h"
 #endif
-
+#include "sys.h"
 #include "usb_lld.h"
 
 #define USB_MAX_PACKET_SIZE 64	/* For FS device */
diff --git a/src/usb_lld.h b/src/usb_lld.h
index cffbfbe..78a35e3 100644
--- a/src/usb_lld.h
+++ b/src/usb_lld.h
@@ -156,6 +156,3 @@ extern void usb_lld_prepare_shutdown (void);
 extern void usb_lld_shutdown (void);
 
 extern void usb_interrupt_handler (void);
-
-extern void usb_lld_sys_init (void);
-extern void usb_lld_sys_shutdown (void);
diff --git a/src/usb_lld_sys.c b/src/usb_lld_sys.c
deleted file mode 100644
index be78d7e..0000000
--- a/src/usb_lld_sys.c
+++ /dev/null
@@ -1,34 +0,0 @@
-#include "ch.h"
-#include "hal.h"
-#include "usb_lld.h"
-
-CH_IRQ_HANDLER (Vector90) {
-  CH_IRQ_PROLOGUE();
-  chSysLockFromIsr();
-
-  usb_interrupt_handler ();
-
-  chSysUnlockFromIsr();
-  CH_IRQ_EPILOGUE();
-}
-
-void usb_lld_sys_init (void)
-{
-  RCC->APB1ENR |= RCC_APB1ENR_USBEN;
-  NVICEnableVector (USB_LP_CAN1_RX0_IRQn,
-		    CORTEX_PRIORITY_MASK (STM32_USB_IRQ_PRIORITY));
-  /*
-   * Note that we also have other IRQ(s):
-   * 	USB_HP_CAN1_TX_IRQn (for double-buffered or isochronous)
-   * 	USBWakeUp_IRQn (suspend/resume)
-   */
-  RCC->APB1RSTR = RCC_APB1RSTR_USBRST;
-  RCC->APB1RSTR = 0;
-
-  USB_Cable_Config (1);
-}
-
-void usb_lld_sys_shutdown (void)
-{
-  RCC->APB1ENR &= ~RCC_APB1ENR_USBEN;
-}