[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>
#include "usb_hid.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 MAINCK = 16Mhz xtal, startup delay is 1.4ms
	// if SLCK slow clock runs at its worst case (max) frequency of 42khz
	// max startup delay = (1.4ms*42k)/8 = 7.356 so round up to 8

	// enable main oscillator and set startup delay
    AT91C_BASE_PMC->PMC_MOR =
        AT91C_CKGR_MOSCEN |
        PMC_MAIN_OSC_STARTUP_DELAY(8);

	// wait for main oscillator to stabilize
	while ( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MOSCS) )
		;

    // PLL output clock frequency in range  80 - 160 MHz needs CKGR_PLL = 00
    // PLL output clock frequency in range 150 - 180 MHz needs CKGR_PLL = 10
    // PLL output is MAINCK * 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 & AT91C_PMC_LOCK) )
		;

	// we want a master clock (MCK) to be PLL clock / 2 = 96Mhz / 2 = 48Mhz
	// datasheet recommends that this register is programmed in two operations
	// when changing to PLL, program the prescaler first then the source
    AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_PRES_CLK_2;

	// wait for main clock ready signal
	while ( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) )
		;

	// set the source to PLL
    AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_PRES_CLK_2 | AT91C_PMC_CSS_PLL_CLK;

	// wait for main clock ready signal
	while ( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) )
		;
}

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) & AT91C_MC_FRDY))
                ;
            if(sr & (AT91C_MC_LOCKE | AT91C_MC_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 =
		AT91C_MC_FWS_1FWS |
		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>
6e82300d	10	#include "usb_hid.h"
15c4dc5a	11
	12	struct common_area common_area __attribute__((section(".commonarea")));
	13	unsigned int start_addr, end_addr, bootrom_unlocked;
	14	extern char _bootrom_start, _bootrom_end, _flash_start, _flash_end;
	15
	16	static void ConfigClocks(void)
	17	{
	18	// we are using a 16 MHz crystal as the basis for everything
	19	// slow clock runs at 32Khz typical regardless of crystal
	20
	21	// enable system clock and USB clock
	22	AT91C_BASE_PMC->PMC_SCER = AT91C_PMC_PCK \| AT91C_PMC_UDP;
	23
	24	// enable the clock to the following peripherals
	25	AT91C_BASE_PMC->PMC_PCER =
	26	(1<<AT91C_ID_PIOA) \|
	27	(1<<AT91C_ID_ADC) \|
	28	(1<<AT91C_ID_SPI) \|
	29	(1<<AT91C_ID_SSC) \|
	30	(1<<AT91C_ID_PWMC) \|
	31	(1<<AT91C_ID_UDP);
	32
0aa4cfc2	33	// worst case scenario, with MAINCK = 16Mhz xtal, startup delay is 1.4ms
	34	// if SLCK slow clock runs at its worst case (max) frequency of 42khz
	35	// max startup delay = (1.4ms*42k)/8 = 7.356 so round up to 8
15c4dc5a	36
	37	// enable main oscillator and set startup delay
	38	AT91C_BASE_PMC->PMC_MOR =
0aa4cfc2	39	AT91C_CKGR_MOSCEN \|
0aa4cfc2	40	PMC_MAIN_OSC_STARTUP_DELAY(8);
15c4dc5a	41
15c4dc5a	42	// wait for main oscillator to stabilize
0aa4cfc2	43	while ( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MOSCS) )
15c4dc5a	44	;
15c4dc5a	45
0aa4cfc2	46	// PLL output clock frequency in range 80 - 160 MHz needs CKGR_PLL = 00
	47	// PLL output clock frequency in range 150 - 180 MHz needs CKGR_PLL = 10
	48	// PLL output is MAINCK * multiplier / divisor = 16Mhz * 12 / 2 = 96Mhz
15c4dc5a	49	AT91C_BASE_PMC->PMC_PLLR =
	50	PMC_PLL_DIVISOR(2) \|
	51	PMC_PLL_COUNT_BEFORE_LOCK(0x50) \|
	52	PMC_PLL_FREQUENCY_RANGE(0) \|
	53	PMC_PLL_MULTIPLIER(12) \|
	54	PMC_PLL_USB_DIVISOR(1);
	55
	56	// wait for PLL to lock
0aa4cfc2	57	while ( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_LOCK) )
15c4dc5a	58	;
	59
	60	// we want a master clock (MCK) to be PLL clock / 2 = 96Mhz / 2 = 48Mhz
0aa4cfc2	61	// datasheet recommends that this register is programmed in two operations
15c4dc5a	62	// when changing to PLL, program the prescaler first then the source
0aa4cfc2	63	AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_PRES_CLK_2;
15c4dc5a	64
15c4dc5a	65	// wait for main clock ready signal
0aa4cfc2	66	while ( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) )
15c4dc5a	67	;
	68
	69	// set the source to PLL
0aa4cfc2	70	AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_PRES_CLK_2 \| AT91C_PMC_CSS_PLL_CLK;
15c4dc5a	71
15c4dc5a	72	// wait for main clock ready signal
0aa4cfc2	73	while ( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) )
15c4dc5a	74	;
	75	}
	76
	77	static void Fatal(void)
	78	{
	79	for(;;);
	80	}
	81
f7e3ed82	82	void UsbPacketReceived(uint8_t *packet, int len)
15c4dc5a	83	{
	84	int i, dont_ack=0;
	85	UsbCommand c = (UsbCommand )packet;
f7e3ed82	86	volatile uint32_t *p;
15c4dc5a	87
	88	if(len != sizeof(*c)) {
	89	Fatal();
	90	}
	91
	92	switch(c->cmd) {
	93	case CMD_DEVICE_INFO:
	94	dont_ack = 1;
	95	c->cmd = CMD_DEVICE_INFO;
	96	c->arg[0] = DEVICE_INFO_FLAG_BOOTROM_PRESENT \| DEVICE_INFO_FLAG_CURRENT_MODE_BOOTROM \|
	97	DEVICE_INFO_FLAG_UNDERSTANDS_START_FLASH;
	98	if(common_area.flags.osimage_present) c->arg[0] \|= DEVICE_INFO_FLAG_OSIMAGE_PRESENT;
	99	UsbSendPacket(packet, len);
	100	break;
	101
	102	case CMD_SETUP_WRITE:
	103	/* The temporary write buffer of the embedded flash controller is mapped to the
	104	* whole memory region, only the last 8 bits are decoded.
	105	*/
f7e3ed82	106	p = (volatile uint32_t *)&_flash_start;
15c4dc5a	107	for(i = 0; i < 12; i++) {
	108	p[i+c->arg[0]] = c->d.asDwords[i];
	109	}
	110	break;
	111
	112	case CMD_FINISH_WRITE:
f7e3ed82	113	p = (volatile uint32_t *)&_flash_start;
15c4dc5a	114	for(i = 0; i < 4; i++) {
	115	p[i+60] = c->d.asDwords[i];
	116	}
	117
	118	/* Check that the address that we are supposed to write to is within our allowed region */
	119	if( ((c->arg[0]+AT91C_IFLASH_PAGE_SIZE-1) >= end_addr) \|\| (c->arg[0] < start_addr) ) {
	120	/* Disallow write */
	121	dont_ack = 1;
	122	c->cmd = CMD_NACK;
	123	UsbSendPacket(packet, len);
	124	} else {
	125	/* Translate address to flash page and do flash, update here for the 512k part */
	126	AT91C_BASE_EFC0->EFC_FCR = MC_FLASH_COMMAND_KEY \|
	127	MC_FLASH_COMMAND_PAGEN((c->arg[0]-(int)&_flash_start)/AT91C_IFLASH_PAGE_SIZE) \|
	128	AT91C_MC_FCMD_START_PROG;
	129	}
e30c654b	130
15c4dc5a	131	uint32_t sr;
e30c654b	132
0aa4cfc2	133	while(!((sr = AT91C_BASE_EFC0->EFC_FSR) & AT91C_MC_FRDY))
15c4dc5a	134	;
0aa4cfc2	135	if(sr & (AT91C_MC_LOCKE \| AT91C_MC_PROGE)) {
15c4dc5a	136	dont_ack = 1;
	137	c->cmd = CMD_NACK;
	138	UsbSendPacket(packet, len);
	139	}
	140	break;
	141
	142	case CMD_HARDWARE_RESET:
	143	USB_D_PLUS_PULLUP_OFF();
	144	AT91C_BASE_RSTC->RSTC_RCR = RST_CONTROL_KEY \| AT91C_RSTC_PROCRST;
	145	break;
	146
	147	case CMD_START_FLASH:
	148	if(c->arg[2] == START_FLASH_MAGIC) bootrom_unlocked = 1;
	149	else bootrom_unlocked = 0;
	150	{
	151	int prot_start = (int)&_bootrom_start;
	152	int prot_end = (int)&_bootrom_end;
	153	int allow_start = (int)&_flash_start;
	154	int allow_end = (int)&_flash_end;
	155	int cmd_start = c->arg[0];
	156	int cmd_end = c->arg[1];
	157
	158	/* Only allow command if the bootrom is unlocked, or the parameters are outside of the protected
	159	* bootrom area. In any case they must be within the flash area.
	160	*/
	161	if( (bootrom_unlocked \|\| ((cmd_start >= prot_end) \|\| (cmd_end < prot_start)))
	162	&& (cmd_start >= allow_start) && (cmd_end <= allow_end) ) {
	163	start_addr = cmd_start;
	164	end_addr = cmd_end;
	165	} else {
	166	start_addr = end_addr = 0;
	167	dont_ack = 1;
	168	c->cmd = CMD_NACK;
	169	UsbSendPacket(packet, len);
	170	}
	171	}
	172	break;
	173
	174	default:
	175	Fatal();
	176	break;
	177	}
	178
	179	if(!dont_ack) {
	180	c->cmd = CMD_ACK;
	181	UsbSendPacket(packet, len);
	182	}
	183	}
	184
	185	static void flash_mode(int externally_entered)
	186	{
	187	start_addr = 0;
	188	end_addr = 0;
	189	bootrom_unlocked = 0;
	190
	191	UsbStart();
	192	for(;;) {
	193	WDT_HIT();
	194
	195	UsbPoll(TRUE);
	196
	197	if(!externally_entered && !BUTTON_PRESS()) {
	198	/* Perform a reset to leave flash mode */
	199	USB_D_PLUS_PULLUP_OFF();
200	LED_B_ON();
201	AT91C_BASE_RSTC->RSTC_RCR = RST_CONTROL_KEY \| AT91C_RSTC_PROCRST;
202	for(;;);
203	}
204	if(externally_entered && BUTTON_PRESS()) {
205	/* Let the user's button press override the automatic leave */
206	externally_entered = 0;
207	}
208	}
209	}
210
211	extern char _osimage_entry;
212	void BootROM(void)
213	{
214	//------------
215	// First set up all the I/O pins; GPIOs configured directly, other ones
216	// just need to be assigned to the appropriate peripheral.
217
218	// Kill all the pullups, especially the one on USB D+; leave them for
219	// the unused pins, though.
220	AT91C_BASE_PIOA->PIO_PPUDR =
221	GPIO_USB_PU \|
222	GPIO_LED_A \|
223	GPIO_LED_B \|
224	GPIO_LED_C \|
225	GPIO_LED_D \|
226	GPIO_FPGA_DIN \|
227	GPIO_FPGA_DOUT \|
228	GPIO_FPGA_CCLK \|
229	GPIO_FPGA_NINIT \|
230	GPIO_FPGA_NPROGRAM \|
231	GPIO_FPGA_DONE \|
232	GPIO_MUXSEL_HIPKD \|
233	GPIO_MUXSEL_HIRAW \|
234	GPIO_MUXSEL_LOPKD \|
235	GPIO_MUXSEL_LORAW \|
236	GPIO_RELAY \|
237	GPIO_NVDD_ON;
238	// (and add GPIO_FPGA_ON)
239	// These pins are outputs
240	AT91C_BASE_PIOA->PIO_OER =
241	GPIO_LED_A \|
242	GPIO_LED_B \|
243	GPIO_LED_C \|
244	GPIO_LED_D \|
245	GPIO_RELAY \|
246	GPIO_NVDD_ON;
247	// PIO controls the following pins
248	AT91C_BASE_PIOA->PIO_PER =
249	GPIO_USB_PU \|
250	GPIO_LED_A \|
251	GPIO_LED_B \|
252	GPIO_LED_C \|
253	GPIO_LED_D;
254
255	USB_D_PLUS_PULLUP_OFF();
256	LED_D_OFF();
257	LED_C_ON();
258	LED_B_OFF();
259	LED_A_OFF();
260
24b182d0	261	AT91C_BASE_EFC0->EFC_FMR =
0aa4cfc2	262	AT91C_MC_FWS_1FWS \|
24b182d0	263	MC_FLASH_MODE_MASTER_CLK_IN_MHZ(48);
15c4dc5a	264
	265	// Initialize all system clocks
	266	ConfigClocks();
	267
	268	LED_A_ON();
	269
	270	int common_area_present = 0;
	271	switch(AT91C_BASE_RSTC->RSTC_RSR & AT91C_RSTC_RSTTYP) {
	272	case AT91C_RSTC_RSTTYP_WATCHDOG:
	273	case AT91C_RSTC_RSTTYP_SOFTWARE:
	274	case AT91C_RSTC_RSTTYP_USER:
	275	/* In these cases the common_area in RAM should be ok, retain it if it's there */
	276	if(common_area.magic == COMMON_AREA_MAGIC && common_area.version == 1) {
	277	common_area_present = 1;
	278	}
	279	break;
	280	default: /* Otherwise, initialize it from scratch */
	281	break;
	282	}
	283
	284	if(!common_area_present){
	285	/* Common area not ok, initialize it */
	286	int i; for(i=0; i<sizeof(common_area); i++) { /* Makeshift memset, no need to drag util.c into this */
	287	((char*)&common_area)[i] = 0;
	288	}
	289	common_area.magic = COMMON_AREA_MAGIC;
	290	common_area.version = 1;
	291	common_area.flags.bootrom_present = 1;
	292	}
	293
	294	common_area.flags.bootrom_present = 1;
	295	if(common_area.command == COMMON_AREA_COMMAND_ENTER_FLASH_MODE) {
	296	common_area.command = COMMON_AREA_COMMAND_NONE;
	297	flash_mode(1);
	298	} else if(BUTTON_PRESS()) {
	299	flash_mode(0);
	300	} else if((uint32_t)&_osimage_entry == 0xffffffffU) {
	301	flash_mode(1);
	302	} else {
	303	// jump to Flash address of the osimage entry point (LSBit set for thumb mode)
902cb3c0	304	__asm("bx %0\n" : : "r" ( ((int)&_osimage_entry) \| 0x1 ) );
15c4dc5a	305	}
15c4dc5a	306	}