[proxmark3-svn] / bootrom / bootrom.c

//-----------------------------------------------------------------------------
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// Main code for the bootloader
//-----------------------------------------------------------------------------

#include <proxmark3.h>

struct common_area common_area __attribute__((section(".commonarea")));
unsigned int start_addr, end_addr, bootrom_unlocked;
extern char _bootrom_start, _bootrom_end, _flash_start, _flash_end;

static void ConfigClocks(void)
{
    // we are using a 16 MHz crystal as the basis for everything
    // slow clock runs at 32Khz typical regardless of crystal

    // enable system clock and USB clock
    AT91C_BASE_PMC->PMC_SCER = AT91C_PMC_PCK | AT91C_PMC_UDP;

	// enable the clock to the following peripherals
    AT91C_BASE_PMC->PMC_PCER =
		(1<<AT91C_ID_PIOA)	|
		(1<<AT91C_ID_ADC)	|
		(1<<AT91C_ID_SPI)	|
		(1<<AT91C_ID_SSC)	|
		(1<<AT91C_ID_PWMC)	|
		(1<<AT91C_ID_UDP);

	// worst case scenario, with 16Mhz xtal startup delay is 14.5ms
	// with a slow clock running at it worst case (max) frequency of 42khz
	// max startup delay = (14.5ms*42k)/8 = 76 = 0x4C round up to 0x50

	// enable main oscillator and set startup delay
    AT91C_BASE_PMC->PMC_MOR =
    	PMC_MAIN_OSC_ENABLE |
        PMC_MAIN_OSC_STARTUP_DELAY(0x50);

	// wait for main oscillator to stabilize
	while ( !(AT91C_BASE_PMC->PMC_SR & PMC_MAIN_OSC_STABILIZED) )
		;

    // minimum PLL clock frequency is 80 MHz in range 00 (96 here so okay)
    // frequency is crystal * multiplier / divisor = 16Mhz * 12 / 2 = 96Mhz
    AT91C_BASE_PMC->PMC_PLLR =
    	PMC_PLL_DIVISOR(2) |
		PMC_PLL_COUNT_BEFORE_LOCK(0x50) |
		PMC_PLL_FREQUENCY_RANGE(0) |
		PMC_PLL_MULTIPLIER(12) |
		PMC_PLL_USB_DIVISOR(1);

	// wait for PLL to lock
	while ( !(AT91C_BASE_PMC->PMC_SR & PMC_MAIN_OSC_PLL_LOCK) )
		;

	// we want a master clock (MCK) to be PLL clock / 2 = 96Mhz / 2 = 48Mhz
	// as per datasheet, this register must be programmed in two operations
	// when changing to PLL, program the prescaler first then the source
    AT91C_BASE_PMC->PMC_MCKR = PMC_CLK_PRESCALE_DIV_2;

	// wait for main clock ready signal
	while ( !(AT91C_BASE_PMC->PMC_SR & PMC_MAIN_OSC_MCK_READY) )
		;

	// set the source to PLL
    AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_CSS_PLL_CLK | PMC_CLK_PRESCALE_DIV_2;

	// wait for main clock ready signal
	while ( !(AT91C_BASE_PMC->PMC_SR & PMC_MAIN_OSC_MCK_READY) )
		;
}

static void Fatal(void)
{
    for(;;);
}

void UsbPacketReceived(uint8_t *packet, int len)
{
    int i, dont_ack=0;
    UsbCommand *c = (UsbCommand *)packet;
    volatile uint32_t *p;

    if(len != sizeof(*c)) {
        Fatal();
    }

    switch(c->cmd) {
        case CMD_DEVICE_INFO:
            dont_ack = 1;
            c->cmd = CMD_DEVICE_INFO;
            c->arg[0] = DEVICE_INFO_FLAG_BOOTROM_PRESENT | DEVICE_INFO_FLAG_CURRENT_MODE_BOOTROM |
                DEVICE_INFO_FLAG_UNDERSTANDS_START_FLASH;
            if(common_area.flags.osimage_present) c->arg[0] |= DEVICE_INFO_FLAG_OSIMAGE_PRESENT;
            UsbSendPacket(packet, len);
            break;

        case CMD_SETUP_WRITE:
            /* The temporary write buffer of the embedded flash controller is mapped to the
             * whole memory region, only the last 8 bits are decoded.
             */
            p = (volatile uint32_t *)&_flash_start;
            for(i = 0; i < 12; i++) {
                p[i+c->arg[0]] = c->d.asDwords[i];
            }
            break;

        case CMD_FINISH_WRITE:
            p = (volatile uint32_t *)&_flash_start;
            for(i = 0; i < 4; i++) {
                p[i+60] = c->d.asDwords[i];
            }

            /* Check that the address that we are supposed to write to is within our allowed region */
            if( ((c->arg[0]+AT91C_IFLASH_PAGE_SIZE-1) >= end_addr) || (c->arg[0] < start_addr) ) {
                /* Disallow write */
                dont_ack = 1;
                c->cmd = CMD_NACK;
                UsbSendPacket(packet, len);
            } else {
                /* Translate address to flash page and do flash, update here for the 512k part */
                AT91C_BASE_EFC0->EFC_FCR = MC_FLASH_COMMAND_KEY |
                    MC_FLASH_COMMAND_PAGEN((c->arg[0]-(int)&_flash_start)/AT91C_IFLASH_PAGE_SIZE) |
                    AT91C_MC_FCMD_START_PROG;
            }

            uint32_t sr;

            while(!((sr = AT91C_BASE_EFC0->EFC_FSR) & MC_FLASH_STATUS_READY))
                ;
            if(sr & (MC_FLASH_STATUS_LOCKE | MC_FLASH_STATUS_PROGE)) {
        	    dont_ack = 1;
                    c->cmd = CMD_NACK;
                    UsbSendPacket(packet, len);
            }
            break;

        case CMD_HARDWARE_RESET:
            USB_D_PLUS_PULLUP_OFF();
            AT91C_BASE_RSTC->RSTC_RCR = RST_CONTROL_KEY | AT91C_RSTC_PROCRST;
            break;

        case CMD_START_FLASH:
            if(c->arg[2] == START_FLASH_MAGIC) bootrom_unlocked = 1;
            else bootrom_unlocked = 0;
            {
                int prot_start = (int)&_bootrom_start;
                int prot_end = (int)&_bootrom_end;
                int allow_start = (int)&_flash_start;
                int allow_end = (int)&_flash_end;
                int cmd_start = c->arg[0];
                int cmd_end = c->arg[1];

                /* Only allow command if the bootrom is unlocked, or the parameters are outside of the protected
                 * bootrom area. In any case they must be within the flash area.
                 */
                if( (bootrom_unlocked || ((cmd_start >= prot_end) || (cmd_end < prot_start)))
                    && (cmd_start >= allow_start) && (cmd_end <= allow_end) ) {
                    start_addr = cmd_start;
                    end_addr = cmd_end;
                } else {
                    start_addr = end_addr = 0;
                    dont_ack = 1;
                    c->cmd = CMD_NACK;
                    UsbSendPacket(packet, len);
                }
            }
            break;

        default:
            Fatal();
            break;
    }

    if(!dont_ack) {
        c->cmd = CMD_ACK;
        UsbSendPacket(packet, len);
    }
}

static void flash_mode(int externally_entered)
{
	start_addr = 0;
	end_addr = 0;
	bootrom_unlocked = 0;

	UsbStart();
	for(;;) {
		WDT_HIT();

		UsbPoll(TRUE);

		if(!externally_entered && !BUTTON_PRESS()) {
			/* Perform a reset to leave flash mode */
			USB_D_PLUS_PULLUP_OFF();
			LED_B_ON();
			AT91C_BASE_RSTC->RSTC_RCR = RST_CONTROL_KEY | AT91C_RSTC_PROCRST;
			for(;;);
		}
		if(externally_entered && BUTTON_PRESS()) {
			/* Let the user's button press override the automatic leave */
			externally_entered = 0;
		}
	}
}

extern char _osimage_entry;
void BootROM(void)
{
    //------------
    // First set up all the I/O pins; GPIOs configured directly, other ones
    // just need to be assigned to the appropriate peripheral.

    // Kill all the pullups, especially the one on USB D+; leave them for
    // the unused pins, though.
    AT91C_BASE_PIOA->PIO_PPUDR =
    	GPIO_USB_PU			|
		GPIO_LED_A			|
		GPIO_LED_B			|
		GPIO_LED_C			|
		GPIO_LED_D			|
		GPIO_FPGA_DIN		|
		GPIO_FPGA_DOUT		|
		GPIO_FPGA_CCLK		|
		GPIO_FPGA_NINIT		|
		GPIO_FPGA_NPROGRAM	|
		GPIO_FPGA_DONE		|
		GPIO_MUXSEL_HIPKD	|
		GPIO_MUXSEL_HIRAW	|
		GPIO_MUXSEL_LOPKD	|
		GPIO_MUXSEL_LORAW	|
		GPIO_RELAY			|
		GPIO_NVDD_ON;
		// (and add GPIO_FPGA_ON)
	// These pins are outputs
    AT91C_BASE_PIOA->PIO_OER =
    	GPIO_LED_A			|
		GPIO_LED_B			|
		GPIO_LED_C			|
		GPIO_LED_D			|
		GPIO_RELAY			|
		GPIO_NVDD_ON;
	// PIO controls the following pins
    AT91C_BASE_PIOA->PIO_PER =
    	GPIO_USB_PU			|
		GPIO_LED_A			|
		GPIO_LED_B			|
		GPIO_LED_C			|
		GPIO_LED_D;

    USB_D_PLUS_PULLUP_OFF();
    LED_D_OFF();
    LED_C_ON();
    LED_B_OFF();
    LED_A_OFF();

	AT91C_BASE_EFC0->EFC_FMR =
		MC_FLASH_MODE_FLASH_WAIT_STATES(1) |
		MC_FLASH_MODE_MASTER_CLK_IN_MHZ(48);

    // Initialize all system clocks
    ConfigClocks();

    LED_A_ON();

    int common_area_present = 0;
    switch(AT91C_BASE_RSTC->RSTC_RSR & AT91C_RSTC_RSTTYP) {
    case AT91C_RSTC_RSTTYP_WATCHDOG:
    case AT91C_RSTC_RSTTYP_SOFTWARE:
    case AT91C_RSTC_RSTTYP_USER:
	    /* In these cases the common_area in RAM should be ok, retain it if it's there */
	    if(common_area.magic == COMMON_AREA_MAGIC && common_area.version == 1) {
		    common_area_present = 1;
	    }
	    break;
    default: /* Otherwise, initialize it from scratch */
	    break;
    }

    if(!common_area_present){
	    /* Common area not ok, initialize it */
	    int i; for(i=0; i<sizeof(common_area); i++) { /* Makeshift memset, no need to drag util.c into this */
		    ((char*)&common_area)[i] = 0;
	    }
	    common_area.magic = COMMON_AREA_MAGIC;
	    common_area.version = 1;
	    common_area.flags.bootrom_present = 1;
    }

    common_area.flags.bootrom_present = 1;
    if(common_area.command == COMMON_AREA_COMMAND_ENTER_FLASH_MODE) {
	    common_area.command = COMMON_AREA_COMMAND_NONE;
	    flash_mode(1);
    } else if(BUTTON_PRESS()) {
	    flash_mode(0);
    } else if(*(uint32_t*)&_osimage_entry == 0xffffffffU) {
	    flash_mode(1);
    } else {
	    // jump to Flash address of the osimage entry point (LSBit set for thumb mode)
	    asm("bx %0\n" : : "r" ( ((int)&_osimage_entry) | 0x1 ) );
    }
}
Commit	Line	Data
bd20f8f4	1	//-----------------------------------------------------------------------------
	2	// This code is licensed to you under the terms of the GNU GPL, version 2 or,
	3	// at your option, any later version. See the LICENSE.txt file for the text of
	4	// the license.
	5	//-----------------------------------------------------------------------------
	6	// Main code for the bootloader
	7	//-----------------------------------------------------------------------------
	8
15c4dc5a	9	#include <proxmark3.h>
	10
	11	struct common_area common_area __attribute__((section(".commonarea")));
	12	unsigned int start_addr, end_addr, bootrom_unlocked;
	13	extern char _bootrom_start, _bootrom_end, _flash_start, _flash_end;
	14
	15	static void ConfigClocks(void)
	16	{
	17	// we are using a 16 MHz crystal as the basis for everything
	18	// slow clock runs at 32Khz typical regardless of crystal
	19
	20	// enable system clock and USB clock
	21	AT91C_BASE_PMC->PMC_SCER = AT91C_PMC_PCK \| AT91C_PMC_UDP;
	22
	23	// enable the clock to the following peripherals
	24	AT91C_BASE_PMC->PMC_PCER =
	25	(1<<AT91C_ID_PIOA) \|
	26	(1<<AT91C_ID_ADC) \|
	27	(1<<AT91C_ID_SPI) \|
	28	(1<<AT91C_ID_SSC) \|
	29	(1<<AT91C_ID_PWMC) \|
	30	(1<<AT91C_ID_UDP);
	31
	32	// worst case scenario, with 16Mhz xtal startup delay is 14.5ms
	33	// with a slow clock running at it worst case (max) frequency of 42khz
	34	// max startup delay = (14.5ms*42k)/8 = 76 = 0x4C round up to 0x50
	35
	36	// enable main oscillator and set startup delay
	37	AT91C_BASE_PMC->PMC_MOR =
	38	PMC_MAIN_OSC_ENABLE \|
	39	PMC_MAIN_OSC_STARTUP_DELAY(0x50);
	40
	41	// wait for main oscillator to stabilize
	42	while ( !(AT91C_BASE_PMC->PMC_SR & PMC_MAIN_OSC_STABILIZED) )
	43	;
	44
	45	// minimum PLL clock frequency is 80 MHz in range 00 (96 here so okay)
	46	// frequency is crystal * multiplier / divisor = 16Mhz * 12 / 2 = 96Mhz
	47	AT91C_BASE_PMC->PMC_PLLR =
	48	PMC_PLL_DIVISOR(2) \|
	49	PMC_PLL_COUNT_BEFORE_LOCK(0x50) \|
	50	PMC_PLL_FREQUENCY_RANGE(0) \|
	51	PMC_PLL_MULTIPLIER(12) \|
	52	PMC_PLL_USB_DIVISOR(1);
	53
	54	// wait for PLL to lock
	55	while ( !(AT91C_BASE_PMC->PMC_SR & PMC_MAIN_OSC_PLL_LOCK) )
	56	;
	57
	58	// we want a master clock (MCK) to be PLL clock / 2 = 96Mhz / 2 = 48Mhz
	59	// as per datasheet, this register must be programmed in two operations
	60	// when changing to PLL, program the prescaler first then the source
	61	AT91C_BASE_PMC->PMC_MCKR = PMC_CLK_PRESCALE_DIV_2;
	62
	63	// wait for main clock ready signal
	64	while ( !(AT91C_BASE_PMC->PMC_SR & PMC_MAIN_OSC_MCK_READY) )
	65	;
	66
	67	// set the source to PLL
	68	AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_CSS_PLL_CLK \| PMC_CLK_PRESCALE_DIV_2;
	69
	70	// wait for main clock ready signal
	71	while ( !(AT91C_BASE_PMC->PMC_SR & PMC_MAIN_OSC_MCK_READY) )
	72	;
73	}
74
75	static void Fatal(void)
76	{
77	for(;;);
78	}
79
f7e3ed82	80	void UsbPacketReceived(uint8_t *packet, int len)
15c4dc5a	81	{
	82	int i, dont_ack=0;
	83	UsbCommand c = (UsbCommand )packet;
f7e3ed82	84	volatile uint32_t *p;
15c4dc5a	85
	86	if(len != sizeof(*c)) {
	87	Fatal();
	88	}
	89
	90	switch(c->cmd) {
	91	case CMD_DEVICE_INFO:
	92	dont_ack = 1;
	93	c->cmd = CMD_DEVICE_INFO;
	94	c->arg[0] = DEVICE_INFO_FLAG_BOOTROM_PRESENT \| DEVICE_INFO_FLAG_CURRENT_MODE_BOOTROM \|
	95	DEVICE_INFO_FLAG_UNDERSTANDS_START_FLASH;
	96	if(common_area.flags.osimage_present) c->arg[0] \|= DEVICE_INFO_FLAG_OSIMAGE_PRESENT;
	97	UsbSendPacket(packet, len);
	98	break;
	99
	100	case CMD_SETUP_WRITE:
	101	/* The temporary write buffer of the embedded flash controller is mapped to the
	102	* whole memory region, only the last 8 bits are decoded.
	103	*/
f7e3ed82	104	p = (volatile uint32_t *)&_flash_start;
15c4dc5a	105	for(i = 0; i < 12; i++) {
	106	p[i+c->arg[0]] = c->d.asDwords[i];
	107	}
	108	break;
	109
	110	case CMD_FINISH_WRITE:
f7e3ed82	111	p = (volatile uint32_t *)&_flash_start;
15c4dc5a	112	for(i = 0; i < 4; i++) {
	113	p[i+60] = c->d.asDwords[i];
	114	}
	115
	116	/* Check that the address that we are supposed to write to is within our allowed region */
	117	if( ((c->arg[0]+AT91C_IFLASH_PAGE_SIZE-1) >= end_addr) \|\| (c->arg[0] < start_addr) ) {
	118	/* Disallow write */
	119	dont_ack = 1;
	120	c->cmd = CMD_NACK;
	121	UsbSendPacket(packet, len);
	122	} else {
	123	/* Translate address to flash page and do flash, update here for the 512k part */
	124	AT91C_BASE_EFC0->EFC_FCR = MC_FLASH_COMMAND_KEY \|
	125	MC_FLASH_COMMAND_PAGEN((c->arg[0]-(int)&_flash_start)/AT91C_IFLASH_PAGE_SIZE) \|
	126	AT91C_MC_FCMD_START_PROG;
	127	}
e30c654b	128
15c4dc5a	129	uint32_t sr;
e30c654b	130
15c4dc5a	131	while(!((sr = AT91C_BASE_EFC0->EFC_FSR) & MC_FLASH_STATUS_READY))
15c4dc5a	132	;
e30c654b	133	if(sr & (MC_FLASH_STATUS_LOCKE \| MC_FLASH_STATUS_PROGE)) {
15c4dc5a	134	dont_ack = 1;
	135	c->cmd = CMD_NACK;
	136	UsbSendPacket(packet, len);
	137	}
	138	break;
	139
	140	case CMD_HARDWARE_RESET:
	141	USB_D_PLUS_PULLUP_OFF();
	142	AT91C_BASE_RSTC->RSTC_RCR = RST_CONTROL_KEY \| AT91C_RSTC_PROCRST;
	143	break;
	144
	145	case CMD_START_FLASH:
	146	if(c->arg[2] == START_FLASH_MAGIC) bootrom_unlocked = 1;
	147	else bootrom_unlocked = 0;
	148	{
	149	int prot_start = (int)&_bootrom_start;
	150	int prot_end = (int)&_bootrom_end;
	151	int allow_start = (int)&_flash_start;
	152	int allow_end = (int)&_flash_end;
	153	int cmd_start = c->arg[0];
	154	int cmd_end = c->arg[1];
	155
	156	/* Only allow command if the bootrom is unlocked, or the parameters are outside of the protected
	157	* bootrom area. In any case they must be within the flash area.
	158	*/
	159	if( (bootrom_unlocked \|\| ((cmd_start >= prot_end) \|\| (cmd_end < prot_start)))
	160	&& (cmd_start >= allow_start) && (cmd_end <= allow_end) ) {
	161	start_addr = cmd_start;
	162	end_addr = cmd_end;
	163	} else {
	164	start_addr = end_addr = 0;
	165	dont_ack = 1;
	166	c->cmd = CMD_NACK;
	167	UsbSendPacket(packet, len);
	168	}
	169	}
	170	break;
	171
	172	default:
	173	Fatal();
	174	break;
	175	}
	176
	177	if(!dont_ack) {
	178	c->cmd = CMD_ACK;
	179	UsbSendPacket(packet, len);
	180	}
	181	}
	182
	183	static void flash_mode(int externally_entered)
	184	{
	185	start_addr = 0;
	186	end_addr = 0;
	187	bootrom_unlocked = 0;
	188
	189	UsbStart();
	190	for(;;) {
	191	WDT_HIT();
	192
	193	UsbPoll(TRUE);
	194
	195	if(!externally_entered && !BUTTON_PRESS()) {
	196	/* Perform a reset to leave flash mode */
	197	USB_D_PLUS_PULLUP_OFF();
198	LED_B_ON();
199	AT91C_BASE_RSTC->RSTC_RCR = RST_CONTROL_KEY \| AT91C_RSTC_PROCRST;
200	for(;;);
201	}
202	if(externally_entered && BUTTON_PRESS()) {
203	/* Let the user's button press override the automatic leave */
204	externally_entered = 0;
205	}
206	}
207	}
208
209	extern char _osimage_entry;
210	void BootROM(void)
211	{
212	//------------
213	// First set up all the I/O pins; GPIOs configured directly, other ones
214	// just need to be assigned to the appropriate peripheral.
215
216	// Kill all the pullups, especially the one on USB D+; leave them for
217	// the unused pins, though.
218	AT91C_BASE_PIOA->PIO_PPUDR =
219	GPIO_USB_PU \|
220	GPIO_LED_A \|
221	GPIO_LED_B \|
222	GPIO_LED_C \|
223	GPIO_LED_D \|
224	GPIO_FPGA_DIN \|
225	GPIO_FPGA_DOUT \|
226	GPIO_FPGA_CCLK \|
227	GPIO_FPGA_NINIT \|
228	GPIO_FPGA_NPROGRAM \|
229	GPIO_FPGA_DONE \|
230	GPIO_MUXSEL_HIPKD \|
231	GPIO_MUXSEL_HIRAW \|
232	GPIO_MUXSEL_LOPKD \|
233	GPIO_MUXSEL_LORAW \|
234	GPIO_RELAY \|
235	GPIO_NVDD_ON;
236	// (and add GPIO_FPGA_ON)
237	// These pins are outputs
238	AT91C_BASE_PIOA->PIO_OER =
239	GPIO_LED_A \|
240	GPIO_LED_B \|
241	GPIO_LED_C \|
242	GPIO_LED_D \|
243	GPIO_RELAY \|
244	GPIO_NVDD_ON;
245	// PIO controls the following pins
246	AT91C_BASE_PIOA->PIO_PER =
247	GPIO_USB_PU \|
248	GPIO_LED_A \|
249	GPIO_LED_B \|
250	GPIO_LED_C \|
251	GPIO_LED_D;
252
253	USB_D_PLUS_PULLUP_OFF();
254	LED_D_OFF();
255	LED_C_ON();
256	LED_B_OFF();
257	LED_A_OFF();
258
24b182d0	259	AT91C_BASE_EFC0->EFC_FMR =
	260	MC_FLASH_MODE_FLASH_WAIT_STATES(1) \|
	261	MC_FLASH_MODE_MASTER_CLK_IN_MHZ(48);
15c4dc5a	262
	263	// Initialize all system clocks
	264	ConfigClocks();
	265
	266	LED_A_ON();
	267
	268	int common_area_present = 0;
	269	switch(AT91C_BASE_RSTC->RSTC_RSR & AT91C_RSTC_RSTTYP) {
	270	case AT91C_RSTC_RSTTYP_WATCHDOG:
	271	case AT91C_RSTC_RSTTYP_SOFTWARE:
	272	case AT91C_RSTC_RSTTYP_USER:
	273	/* In these cases the common_area in RAM should be ok, retain it if it's there */
	274	if(common_area.magic == COMMON_AREA_MAGIC && common_area.version == 1) {
	275	common_area_present = 1;
	276	}
	277	break;
	278	default: /* Otherwise, initialize it from scratch */
	279	break;
	280	}
	281
	282	if(!common_area_present){
	283	/* Common area not ok, initialize it */
	284	int i; for(i=0; i<sizeof(common_area); i++) { /* Makeshift memset, no need to drag util.c into this */
	285	((char*)&common_area)[i] = 0;
	286	}
	287	common_area.magic = COMMON_AREA_MAGIC;
	288	common_area.version = 1;
	289	common_area.flags.bootrom_present = 1;
	290	}
	291
	292	common_area.flags.bootrom_present = 1;
	293	if(common_area.command == COMMON_AREA_COMMAND_ENTER_FLASH_MODE) {
	294	common_area.command = COMMON_AREA_COMMAND_NONE;
	295	flash_mode(1);
	296	} else if(BUTTON_PRESS()) {
	297	flash_mode(0);
	298	} else if((uint32_t)&_osimage_entry == 0xffffffffU) {
	299	flash_mode(1);
	300	} else {
	301	// jump to Flash address of the osimage entry point (LSBit set for thumb mode)
	302	asm("bx %0\n" : : "r" ( ((int)&_osimage_entry) \| 0x1 ) );
	303	}
	304	}