X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/4ab6281664b86264408b661038c050d0d5932fd7..refs/pull/55/head:/bootrom/bootrom.c

diff --git a/bootrom/bootrom.c b/bootrom/bootrom.c
index 83794d9f..c2c81a9d 100644
--- a/bootrom/bootrom.c
+++ b/bootrom/bootrom.c
@@ -1,304 +1,328 @@
-#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(BYTE *packet, int len)
-{
-    int i, dont_ack=0;
-    UsbCommand *c = (UsbCommand *)packet;
-    volatile DWORD *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 DWORD *)&_flash_start;
-            for(i = 0; i < 12; i++) {
-                p[i+c->arg[0]] = c->d.asDwords[i];
-            }
-            break;
-
-        case CMD_FINISH_WRITE:
-            p = (volatile DWORD *)&_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();
-
-    // if 512K FLASH part - TODO make some defines :)
-    if ((AT91C_BASE_DBGU->DBGU_CIDR | 0xf00) == 0xa00) {
-	    AT91C_BASE_EFC0->EFC_FMR =
-	    	MC_FLASH_MODE_FLASH_WAIT_STATES(1) |
-			MC_FLASH_MODE_MASTER_CLK_IN_MHZ(0x48);
-	    AT91C_BASE_EFC1->EFC_FMR =
-	    	MC_FLASH_MODE_FLASH_WAIT_STATES(1) |
-			MC_FLASH_MODE_MASTER_CLK_IN_MHZ(0x48);
-    } else {
-	    AT91C_BASE_EFC0->EFC_FMR =
-	    	MC_FLASH_MODE_FLASH_WAIT_STATES(0) |
-			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 {
-	    // jump to Flash address of the osimage entry point (LSBit set for thumb mode)
-	    asm("bx %0\n" : : "r" ( ((int)&_osimage_entry) | 0x1 ) );
-    }
-}
+//-----------------------------------------------------------------------------
+// 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_cdc.h"
+#include "cmd.h"
+//#include "usb_hid.h"
+
+void DbpString(char *str) {
+  byte_t len = 0;
+  while (str[len] != 0x00) {
+    len++;
+  }
+  cmd_send(CMD_DEBUG_PRINT_STRING,len,0,0,(byte_t*)str,len);
+}
+
+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(UsbCommand)) {
+    Fatal();
+  }
+  
+  uint32_t arg0 = (uint32_t)c->arg[0];
+  
+  switch(c->cmd) {
+    case CMD_DEVICE_INFO: {
+      dont_ack = 1;
+      arg0 = DEVICE_INFO_FLAG_BOOTROM_PRESENT | DEVICE_INFO_FLAG_CURRENT_MODE_BOOTROM |
+      DEVICE_INFO_FLAG_UNDERSTANDS_START_FLASH;
+      if(common_area.flags.osimage_present) {
+        arg0 |= DEVICE_INFO_FLAG_OSIMAGE_PRESENT;
+      }
+      cmd_send(CMD_DEVICE_INFO,arg0,1,2,0,0);
+    } 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+arg0] = c->d.asDwords[i];
+      }
+    } break;
+      
+    case CMD_FINISH_WRITE: {
+      uint32_t* flash_mem = (uint32_t*)(&_flash_start);
+      for (size_t j=0; j<2; j++) {
+        for(i = 0+(64*j); i < 64+(64*j); i++) {
+          flash_mem[i] = c->d.asDwords[i];
+        }
+        
+        uint32_t flash_address = arg0 + (0x100*j);
+        
+        /* Check that the address that we are supposed to write to is within our allowed region */
+        if( ((flash_address+AT91C_IFLASH_PAGE_SIZE-1) >= end_addr) || (flash_address < start_addr) ) {
+          /* Disallow write */
+          dont_ack = 1;
+          cmd_send(CMD_NACK,0,0,0,0,0);
+        } else {
+          uint32_t page_n = (flash_address - ((uint32_t)flash_mem)) / AT91C_IFLASH_PAGE_SIZE;
+          /* 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(page_n) |
+          AT91C_MC_FCMD_START_PROG;
+        }
+        
+        // Wait until flashing of page finishes
+        uint32_t sr;
+        while(!((sr = AT91C_BASE_EFC0->EFC_FSR) & AT91C_MC_FRDY));
+        if(sr & (AT91C_MC_LOCKE | AT91C_MC_PROGE)) {
+          dont_ack = 1;
+          cmd_send(CMD_NACK,0,0,0,0,0);
+        }
+      }
+    } break;
+      
+    case CMD_HARDWARE_RESET: {
+      usb_disable();
+      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;
+          cmd_send(CMD_NACK,0,0,0,0,0);
+        }
+      }
+    } break;
+      
+    default: {
+      Fatal();
+    } break;
+  }
+  
+  if(!dont_ack) {
+    cmd_send(CMD_ACK,arg0,0,0,0,0);
+  }
+}
+
+static void flash_mode(int externally_entered)
+{
+	start_addr = 0;
+	end_addr = 0;
+	bootrom_unlocked = 0;
+  byte_t rx[sizeof(UsbCommand)];
+	size_t rx_len;
+
+  usb_enable();
+  for (volatile size_t i=0; i<0x100000; i++);
+
+	for(;;) {
+		WDT_HIT();
+
+    if (usb_poll()) {
+      rx_len = usb_read(rx,sizeof(UsbCommand));
+      if (rx_len) {
+        UsbPacketReceived(rx,rx_len);
+      }
+    }
+
+		if(!externally_entered && !BUTTON_PRESS()) {
+			/* Perform a reset to leave flash mode */
+      usb_disable();
+			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 uint32_t _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();
+  usb_disable();
+    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(_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 ) );
+    }
+}