DFU working - but no signature validation for now.

13 files changed, 736 insertions, 230 deletions

diff --git a/Makefile b/Makefile
index b6e38d8..e2159ed 100644
--- a/Makefile
+++ b/Makefile
@@ -59,6 +59,7 @@ export BOARD_OBJS = \
 	$(TOPLEVEL)/stm-fpgacfg.o \
 	$(TOPLEVEL)/stm-keystore.o \
 	$(TOPLEVEL)/stm-sdram.o \
+	$(TOPLEVEL)/stm-flash.o \
 	$(TOPLEVEL)/syscalls.o \
 	$(BOARD_DIR)/TOOLCHAIN_GCC_ARM/startup_stm32f429xx.o \
 	$(BOARD_DIR)/system_stm32f4xx.o \
diff --git a/README.md b/README.md
index 3784aad..90bbdb5 100644
--- a/README.md
+++ b/README.md
@@ -65,6 +65,13 @@ blue LED five times in one second, and then execution of the LED test
 firmware will begin. The LED test firmware will flash the green, yellow,
 red and blue LEDs in order until the end of time.
 
+Once the bootloader is installed, regular firmware can be loaded without
+an ST-LINK cable like this:
+
+  $ ./bin/dfu projects/board-test/led-test.bin
+
+Then reboot the Alpha board.
+
 
 ST-LINK
 =======
diff --git a/bin/dfu b/bin/dfu
new file mode 100755
index 0000000..e270438
--- /dev/null
+++ b/bin/dfu
@@ -0,0 +1,179 @@
+#!/usr/bin/python
+#
+# Copyright (c) 2016, NORDUnet A/S All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+# - Redistributions of source code must retain the above copyright notice,
+#   this list of conditions and the following disclaimer.
+#
+# - Redistributions in binary form must reproduce the above copyright
+#   notice, this list of conditions and the following disclaimer in the
+#   documentation and/or other materials provided with the distribution.
+#
+# - Neither the name of the NORDUnet nor the names of its contributors may
+#   be used to endorse or promote products derived from this software
+#   without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+# IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+# TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+"""
+Utility to transfer a new firmware to the bootloader.
+
+Example usage:
+
+   ./bin/dfu path/to/firmware.bin
+
+Then reset the Cryptech Alpha board.
+"""
+import os
+import sys
+import time
+import struct
+import serial
+import argparse
+
+from binascii import crc32
+
+CHUNK_SIZE = 4096
+
+
+def parse_args():
+    """
+    Parse the command line arguments
+    """
+    parser = argparse.ArgumentParser(description = "Device firmware upgrader",
+                                     add_help = True,
+                                     formatter_class = argparse.ArgumentDefaultsHelpFormatter,
+                                     )
+
+    parser.add_argument('--verbose',
+                        dest='verbose',
+                        action='store_true', default=False,
+                        help='Verbose operation',
+                        )
+
+    parser.add_argument('--device',
+                        dest='device',
+                        default='/dev/ttyUSB0',
+                        help='Name of management port USB serial device',
+                        )
+
+    # positional argument(s)
+    parser.add_argument('filename')
+
+    return parser.parse_args()
+
+
+def _write(dst, data):
+    for i in range(len(data)):
+        dst.write(data[i])
+        time.sleep(0.1)
+    if len(data) == 4:
+        print("Wrote 0x{:02x}{:02x}{:02x}{:02x}".format(ord(data[0]), ord(data[1]), ord(data[2]), ord(data[3])))
+    else:
+        print("Wrote {!r}".format(data))
+
+
+def _read(dst, verbose=False):
+    res = ''
+    while True:
+        x = dst.read(1)
+        if not x:
+            break
+        res += x
+    if res and verbose:
+        print ("Read {!r}".format(res))
+    return res
+
+
+def send_file(filename, args):
+    s = os.stat(filename)
+    size = s.st_size
+    src = open(filename, 'rb')
+    chunk_size = CHUNK_SIZE
+
+    print("Waiting for contact with the bootloader on device {!s}, reset the CrypTech Alpha...".format(args.device))
+
+    while True:
+        try:
+            dst = serial.Serial(args.device, 921600, timeout=0.1)
+        except serial.SerialException:
+            time.sleep(0.2)
+            continue
+        dst.write('\r')
+        response = _read(dst, args.verbose)
+        if 'OK' in response:
+            dst.timeout=2
+            break
+
+    print('\nUploading firmware\n')
+
+    crc = 0
+    counter = 0
+    # 1. Write size of file (4 bytes)
+    _write(dst, struct.pack('<I', size))
+    _read(dst, args.verbose)
+    # 2. Write file contents while calculating CRC-32
+    while True:
+        data = src.read(chunk_size)
+        if not data:
+            break
+        dst.write(data)
+        print("Wrote {!s} bytes (chunk {!s}/{!s})".format(len(data), counter, int(size / chunk_size)))
+        # read ACK (a counter of number of 4k chunks received)
+        while True:
+            ack_bytes = dst.read(4)
+            if len(ack_bytes) == 4:
+                break
+            print('ERROR: Did not receive an ACK, got {!r}'.format(ack_bytes))
+            dst.write('\r')  # eventually get back to the CLI prompt
+        ack = struct.unpack('<I', ack_bytes)[0]
+        if ack != counter + 1:
+            print('ERROR: Did not receive the expected counter as ACK (got {!r}/{!r}, not {!r})'.format(ack, ack_bytes, counter))
+            flush = dst.read(100)
+            print('FLUSH data: {!r}'.format(flush))
+            return False
+        counter += 1
+
+        crc = crc32(data, crc) & 0xffffffff
+
+    _read(dst, args.verbose)
+
+    # 3. Write CRC-32 (4 bytes)
+    _write(dst, struct.pack('<I', crc))
+
+    if args.verbose:
+        print('\nFinished - this command might hang now depending on the firmware loaded')
+        _read(dst, args.verbose)
+    else:
+        print('\nFinished uploading firmware')
+
+    src.close()
+    dst.close()
+    return True
+
+
+def main(args):
+    send_file(args.filename, args)
+    return True
+
+if __name__ == '__main__':
+    try:
+        args = parse_args()
+        if main(args):
+            sys.exit(0)
+        sys.exit(1)
+    except KeyboardInterrupt:
+        pass
+
diff --git a/projects/bootloader/Makefile b/projects/bootloader/Makefile
index 7cef633..4eef758 100644
--- a/projects/bootloader/Makefile
+++ b/projects/bootloader/Makefile
@@ -1,8 +1,10 @@
 PROG = bootloader
 
+OBJS = crc32.o dfu.o
+
 all: $(PROG:=.elf)
 
-%.elf: %.o $(BOARD_OBJS) $(LIBS)
+%.elf: %.o $(BOARD_OBJS) $(OBJS) $(LIBS)
 	$(CC) $(CFLAGS) $^ -o $@ -T$(BOOTLOADER_LDSCRIPT) -g -Wl,-Map=$*.map
 	$(OBJCOPY) -O ihex $*.elf $*.hex
 	$(OBJCOPY) -O binary $*.elf $*.bin
diff --git a/projects/bootloader/bootloader.c b/projects/bootloader/bootloader.c
index 1450c1a..ab3c1d9 100644
--- a/projects/bootloader/bootloader.c
+++ b/projects/bootloader/bootloader.c
@@ -1,22 +1,41 @@
 /*
+ * bootloader.c
+ * ------------
  * Bootloader to either install new firmware received from the MGMT UART,
  * or jump to previously installed firmware.
  *
+ * Copyright (c) 2016, NORDUnet A/S All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of the NORDUnet nor the names of its contributors may
+ *   be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
-#include "stm32f4xx_hal.h"
 #include "stm-init.h"
 #include "stm-led.h"
 #include "stm-uart.h"
-
-/* Magic bytes to signal the bootloader it should jump to the firmware
- * instead of trying to receive a new firmware using the MGMT UART.
- */
-#define HARDWARE_EARLY_DFU_JUMP   0xBADABADA
-
-/* symbols defined in the linker script (STM32F429BI.ld) */
-extern uint32_t CRYPTECH_FIRMWARE_START;
-extern uint32_t CRYPTECH_FIRMWARE_END;
-extern uint32_t CRYPTECH_DFU_CONTROL;
+#include "dfu.h"
 
 /* Linker symbols are strange in C. Make regular pointers for sanity. */
 __IO uint32_t *dfu_control = &CRYPTECH_DFU_CONTROL;
@@ -42,10 +61,30 @@ void do_early_dfu_jump(void)
     while (1);
 }
 
+int should_dfu()
+{
+    int i;
+    uint8_t rx = 0;
+
+    /* While blinking the blue LED for one second, see if we receive a CR on the MGMT UART.
+     * We've discussed also requiring one or both of the FPGA config jumpers installed
+     * before allowing DFU of the STM32 - that check could be done here.
+     */
+    led_on(LED_BLUE);
+    for (i = 0; i < 10; i++) {
+	HAL_Delay(100);
+	led_toggle(LED_BLUE);
+	if (uart_recv_char2(STM_UART_MGMT, &rx, 0) == HAL_OK) {
+	    if (rx == 13) return 1;
+	}
+    }
+    return 0;
+}
+
 int
 main()
 {
-    int i;
+    int status;
 
     /* Check if we've just rebooted in order to jump to the firmware. */
     if (*dfu_control == HARDWARE_EARLY_DFU_JUMP) {
@@ -55,14 +94,23 @@ main()
 
     stm_init();
 
-    uart_send_string2(STM_UART_MGMT, (char *) "This is the bootloader speaking...");
-
-    /* This is where uploading of new firmware over UART could happen */
+    uart_send_string2(STM_UART_MGMT, (char *) "\r\n\r\nThis is the bootloader speaking...");
 
-    led_on(LED_BLUE);
-    for (i = 0; i < 10; i++) {
-	HAL_Delay(100);
-	led_toggle(LED_BLUE);
+    if (should_dfu()) {
+	led_off(LED_BLUE);
+	if ((status = dfu_receive_firmware()) != 0) {
+	    /* Upload of new firmware failed, reboot after lighting the red LED
+	     * for three seconds.
+	     */
+	    led_off(LED_BLUE);
+	    led_on(LED_RED);
+	    uart_send_string2(STM_UART_MGMT, (char *) "dfu_receive_firmware failed: ");
+	    uart_send_number2(STM_UART_MGMT, status, 3, 16);
+	    uart_send_string2(STM_UART_MGMT, (char *) "\r\n\r\nRebooting in three seconds\r\n");
+	    HAL_Delay(3000);
+	    HAL_NVIC_SystemReset();
+	    while (1) {};
+	}
     }
 
     /* Set dfu_control to the magic value that will cause the us to call do_early_dfu_jump
@@ -70,7 +118,7 @@ main()
      */
     *dfu_control = HARDWARE_EARLY_DFU_JUMP;
 
-    uart_send_string2(STM_UART_MGMT, (char *) "loading firmware\r\n");
+    uart_send_string2(STM_UART_MGMT, (char *) "loading firmware\r\n\r\n");
 
     /* De-initialize hardware by rebooting */
     HAL_NVIC_SystemReset();
diff --git a/projects/bootloader/crc32.c b/projects/bootloader/crc32.c
new file mode 100644
index 0000000..4d1a0bc
--- /dev/null
+++ b/projects/bootloader/crc32.c
@@ -0,0 +1,62 @@
+/* Reference code from RFC1952. Not meant to be used outside test code. */
+
+#include "stm32f4xx_hal.h"
+
+
+/* Table of CRCs of all 8-bit messages. */
+unsigned long crc_table[256];
+
+/* Flag: has the table been computed? Initially false. */
+int crc_table_computed = 0;
+
+/* Make the table for a fast CRC. */
+void make_crc_table(void)
+{
+    unsigned long c;
+
+    int n, k;
+    for (n = 0; n < 256; n++) {
+	c = (unsigned long) n;
+	for (k = 0; k < 8; k++) {
+	    if (c & 1) {
+		c = 0xedb88320L ^ (c >> 1);
+	    } else {
+		c = c >> 1;
+	    }
+	}
+	crc_table[n] = c;
+    }
+    crc_table_computed = 1;
+}
+
+/*
+  Update a running crc with the bytes buf[0..len-1] and return
+  the updated crc. The crc should be initialized to zero. Pre- and
+  post-conditioning (one's complement) is performed within this
+  function so it shouldn't be done by the caller. Usage example:
+
+  unsigned long crc = 0L;
+
+  while (read_buffer(buffer, length) != EOF) {
+  crc = update_crc(crc, buffer, length);
+  }
+  if (crc != original_crc) error();
+*/
+uint32_t update_crc(uint32_t crc, uint8_t *buf, int len)
+{
+    unsigned long c = crc ^ 0xffffffffL;
+    int n;
+
+    if (!crc_table_computed)
+	make_crc_table();
+    for (n = 0; n < len; n++) {
+	c = crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
+    }
+    return c ^ 0xffffffffL;
+}
+
+/* Return the CRC of the bytes buf[0..len-1]. */
+unsigned long crc(unsigned char *buf, int len)
+{
+    return update_crc(0L, buf, len);
+}
diff --git a/projects/bootloader/dfu.c b/projects/bootloader/dfu.c
new file mode 100644
index 0000000..231e388
--- /dev/null
+++ b/projects/bootloader/dfu.c
@@ -0,0 +1,106 @@
+/*
+ * dfu.c
+ * ------------
+ * Receive new firmware from MGMT UART and write it to STM32 internal flash.
+ *
+ * Copyright (c) 2016, NORDUnet A/S All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of the NORDUnet nor the names of its contributors may
+ *   be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "dfu.h"
+#include "stm-led.h"
+#include "stm-uart.h"
+#include "stm-flash.h"
+
+#include <string.h>
+
+extern uint32_t update_crc(uint32_t crc, uint8_t *buf, int len);
+
+
+int dfu_receive_firmware(void)
+{
+    uint32_t filesize = 0, crc = 0, my_crc = 0, counter = 0;
+    uint32_t offset = DFU_FIRMWARE_ADDR, n = DFU_UPLOAD_CHUNK_SIZE;
+    uint32_t buf[DFU_UPLOAD_CHUNK_SIZE / 4];
+
+    uart_send_string2(STM_UART_MGMT, (char *) "\r\nOK, bootloader waiting for new firmware\r\n");
+
+    /* Read file size (4 bytes) */
+    uart_receive_bytes(STM_UART_MGMT, (void *) &filesize, 4, 1000);
+    if (filesize < 512 || filesize > DFU_FIRMWARE_END_ADDR - DFU_FIRMWARE_ADDR) {
+	return -1;
+    }
+
+    HAL_FLASH_Unlock();
+
+    while (filesize) {
+	/* By initializing buf to the same value that erased flash has (0xff), we don't
+	 * have to try and be smart when writing the last page of data to the memory.
+	 */
+	memset(buf, 0xffffffff, sizeof(buf));
+
+	if (filesize < n) {
+	    n = filesize;
+	}
+
+	if (uart_receive_bytes(STM_UART_MGMT, (void *) &buf, n, 1000) != HAL_OK) {
+	    return -2;
+	}
+	filesize -= n;
+
+	/* After reception of a chunk but before ACKing we have "all" the time in the world to
+	 * calculate CRC and write it to flash.
+	 */
+	my_crc = update_crc(my_crc, (uint8_t *) buf, n);
+	stm_flash_write32(offset, buf, sizeof(buf) / 4);
+	offset += DFU_UPLOAD_CHUNK_SIZE;
+
+	/* ACK this chunk by sending the current chunk counter (4 bytes) */
+	counter++;
+	uart_send_bytes(STM_UART_MGMT, (void *) &counter, 4);
+	led_toggle(LED_BLUE);
+    }
+
+    HAL_FLASH_Lock();
+
+    /* The sending side will now send it's calculated CRC-32 */
+    uart_receive_bytes(STM_UART_MGMT, (void *) &crc, 4, 1000);
+    if (crc == my_crc) {
+	uart_send_string2(STM_UART_MGMT, (char *) "\r\nSuccess\r\n");
+	return 0;
+    }
+
+    led_on(LED_RED);
+    led_on(LED_YELLOW);
+
+    /* Better to erase the known bad firmware */
+    stm_flash_erase_sectors(DFU_FIRMWARE_ADDR, DFU_FIRMWARE_END_ADDR);
+
+    led_off(LED_YELLOW);
+
+    return 0;
+}
diff --git a/projects/bootloader/dfu.h b/projects/bootloader/dfu.h
new file mode 100644
index 0000000..8dfed9d
--- /dev/null
+++ b/projects/bootloader/dfu.h
@@ -0,0 +1,62 @@
+/*
+ * dfu.h
+ * ---------
+ * Device Firmware Upgrade defines and prototypes.
+ *
+ * Copyright (c) 2016, NORDUnet A/S All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of the NORDUnet nor the names of its contributors may
+ *   be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __STM32_BOOTLOADER_DFU_H
+#define __STM32_BOOTLOADER_DFU_H
+
+#include "stm-init.h"
+
+/* symbols defined in the linker script (STM32F429BI_bootloader.ld) */
+extern uint32_t CRYPTECH_FIRMWARE_START;
+extern uint32_t CRYPTECH_FIRMWARE_END;
+extern uint32_t CRYPTECH_DFU_CONTROL;
+
+#define DFU_FIRMWARE_ADDR         ((uint32_t) &CRYPTECH_FIRMWARE_START)
+#define DFU_FIRMWARE_END_ADDR     ((uint32_t) &CRYPTECH_FIRMWARE_END)
+#define DFU_UPLOAD_CHUNK_SIZE     4096
+
+/* Magic bytes to signal the bootloader it should jump to the firmware
+ * instead of trying to receive a new firmware using the MGMT UART.
+ */
+#define HARDWARE_EARLY_DFU_JUMP   0xBADABADA
+
+extern __IO uint32_t *dfu_control;
+extern __IO uint32_t *dfu_firmware;
+extern __IO uint32_t *dfu_msp_ptr;
+extern __IO uint32_t *dfu_code_ptr;
+
+extern int dfu_receive_firmware(void);
+
+
+#endif /* __STM32_BOOTLOADER_DFU_H */
diff --git a/projects/cli-test/cli-test.c b/projects/cli-test/cli-test.c
index 30623a4..84c268b 100644
--- a/projects/cli-test/cli-test.c
+++ b/projects/cli-test/cli-test.c
@@ -397,7 +397,7 @@ void configure_cli_test(struct cli_def *cli)
     cli_command_node(test, sdram, "Run SDRAM tests");
 }
 
-void configure_cli_misc(struct cli_def *cli)
+static void configure_cli_misc(struct cli_def *cli)
 {
     /* filetransfer */
     cli_command_root_node(filetransfer, "Test file transfering");
@@ -405,11 +405,32 @@ void configure_cli_misc(struct cli_def *cli)
     cli_command_root_node(reboot, "Reboot the STM32");
 }
 
+typedef  void (*pFunction)(void);
+
+/* This is it's own function to make it more convenient to set a breakpoint at it in gdb */
+void do_early_dfu_jump(void)
+{
+    pFunction loaded_app = (pFunction) *dfu_code_ptr;
+    /* Set the stack pointer to the correct one for the firmware */
+    __set_MSP(*dfu_msp_ptr);
+    /* Set the Vector Table Offset Register */
+    SCB->VTOR = (uint32_t) dfu_firmware;
+    loaded_app();
+    while (1);
+}
+
+
 int
 main()
 {
     static struct cli_def cli;
 
+    /* Check if we've just rebooted in order to jump to the firmware. */
+    if (*dfu_control == HARDWARE_EARLY_DFU_JUMP) {
+	*dfu_control = 0;
+	do_early_dfu_jump();
+    }
+
     stm_init();
 
     led_on(LED_RED);
diff --git a/projects/cli-test/mgmt-dfu.c b/projects/cli-test/mgmt-dfu.c
index 33c6e2e..27fd722 100644
--- a/projects/cli-test/mgmt-dfu.c
+++ b/projects/cli-test/mgmt-dfu.c
@@ -1,7 +1,7 @@
 /*
  * mgmt-dfu.c
  * ---------
- * Management CLI Device Firmware Upgrade code.
+ * CLI code for looking at, jumping to or erasing the loaded firmware.
  *
  * Copyright (c) 2016, NORDUnet A/S All rights reserved.
  *
@@ -35,188 +35,31 @@
 #include "stm-init.h"
 #include "mgmt-cli.h"
 #include "stm-uart.h"
-#include "cmsis_nvic.h"
+#include "stm-flash.h"
+#include "mgmt-dfu.h"
 
 #include <string.h>
 
 extern uint32_t update_crc(uint32_t crc, uint8_t *buf, int len);
 
-/* symbols defined in the linker script (STM32F429BI.ld) */
-extern uint32_t CRYPTECH_FIRMWARE_START;
-extern uint32_t CRYPTECH_FIRMWARE_END;
-extern uint32_t CRYPTECH_DFU_CONTROL;
-
-#define DFU_FIRMWARE_ADDR         ((uint32_t ) &CRYPTECH_FIRMWARE_START)
-#define DFU_FIRMWARE_PTR	  ((__IO uint32_t *) (CRYPTECH_FIRMWARE_START))
-#define DFU_FIRMWARE_END_ADDR     CRYPTECH_FIRMWARE_END
-#define HARDWARE_EARLY_DFU_JUMP   0xBADABADA
-#define DFU_UPLOAD_CHUNK_SIZE     256
-
+/* Linker symbols are strange in C. Make regular pointers for sanity. */
 __IO uint32_t *dfu_control = &CRYPTECH_DFU_CONTROL;
-__IO uint32_t *dfu_new_msp = &CRYPTECH_FIRMWARE_START;
-__IO uint32_t *dfu_firmware = &CRYPTECH_FIRMWARE_START + 1;
-
-/* Flash sector offsets from RM0090, Table 6. Flash module - 2 Mbyte dual bank organization */
-#define FLASH_NUM_SECTORS 24 + 1
-uint32_t flash_sector_offsets[FLASH_NUM_SECTORS] = {
-    /* Bank 1 */
-    0x08000000, /* #0,  16 KBytes */
-    0x08004000, /* #1,  16 Kbytes */
-    0x08008000, /* #2,  16 Kbytes */
-    0x0800C000, /* #3,  16 Kbytes */
-    0x08010000, /* #4,  64 Kbytes */
-    0x08020000, /* #5,  128 Kbytes */
-    0x08040000, /* #6,  128 Kbytes */
-    0x08060000, /* #7,  128 Kbytes */
-    0x08080000, /* #8,  128 Kbytes */
-    0x080A0000, /* #9,  128 Kbytes */
-    0x080C0000, /* #10, 128 Kbytes */
-    0x080E0000, /* #11, 128 Kbytes */
-    /* Bank 2 */
-    0x08100000, /* #12,  16 Kbytes */
-    0x08104000, /* #13,  16 Kbytes */
-    0x08108000, /* #14,  16 Kbytes */
-    0x0810C000, /* #15,  16 Kbytes */
-    0x08110000, /* #16,  64 Kbytes */
-    0x08120000, /* #17, 128 Kbytes */
-    0x08140000, /* #18, 128 Kbytes */
-    0x08160000, /* #19, 128 Kbytes */
-    0x08180000, /* #20, 128 Kbytes */
-    0x081A0000, /* #21, 128 Kbytes */
-    0x081C0000, /* #22, 128 Kbytes */
-    0x081E0000, /* #23, 128 Kbytes */
-    0x08200000  /* first address *after* flash */
-};
-
-
-typedef  void (*pFunction)(void);
-
-
-/* This is it's own function to make it more convenient to set a breakpoint at it in gdb */
-void do_early_dfu_jump(void)
-{
-    //pFunction loaded_app = (pFunction) *(DFU_FIRMWARE_PTR + 1);
-    pFunction loaded_app = (pFunction) *dfu_firmware;
-    *dfu_control = 0;
-    __set_MSP(*dfu_new_msp);
-    /* Set the Vector Table Offset Register */
-    SCB->VTOR = DFU_FIRMWARE_ADDR;
-    loaded_app();
-    while (1);
-}
-
-/* This function is called from main() before any peripherals are initialized */
-void check_early_dfu_jump(void)
-{
-    if (*dfu_control == HARDWARE_EARLY_DFU_JUMP) {
-	do_early_dfu_jump();
-    }
-}
-
-inline int _flash_sector_num(uint32_t offset)
-{
-    int i = FLASH_NUM_SECTORS - 1;
-    while (i-- >= 0) {
-	if (offset >= flash_sector_offsets[i] &&
-	    offset < flash_sector_offsets[i + 1]) {
-	    return i;
-	}
-    }
-    return -1;
-}
-
-int _write_to_flash(uint32_t offset, const uint32_t *buf, uint32_t elements)
-{
-    uint32_t sector = _flash_sector_num(offset);
-    uint32_t SectorError = 0, i, j;
-
-    if (offset == flash_sector_offsets[sector]) {
-	/* Request to write to beginning of a flash sector, erase it first. */
-	FLASH_EraseInitTypeDef FLASH_EraseInitStruct;
-
-	FLASH_EraseInitStruct.TypeErase = TYPEERASE_SECTORS;
-	FLASH_EraseInitStruct.Sector = sector;
-	FLASH_EraseInitStruct.NbSectors = 1;
-	FLASH_EraseInitStruct.VoltageRange = VOLTAGE_RANGE_3;
-
-	if (HAL_FLASHEx_Erase(&FLASH_EraseInitStruct, &SectorError) != HAL_OK) {
-	    return -1;
-	}
-    }
-
-    for (i = 0; i < elements; i++) {
-	if ((j = HAL_FLASH_Program(FLASH_TYPEPROGRAM_WORD, offset, buf[i])) != HAL_OK) {
-	    return -2;
-	}
-	offset += 4;
-    }
-
-    return 1;
-}
-
-int cmd_dfu_upload(struct cli_def *cli, const char *command, char *argv[], int argc)
-{
-    uint32_t filesize = 0, crc = 0, my_crc = 0, counter = 0;
-    uint32_t offset = DFU_FIRMWARE_ADDR, n = DFU_UPLOAD_CHUNK_SIZE;
-    uint32_t buf[DFU_UPLOAD_CHUNK_SIZE / 4];
-
-    cli_print(cli, "OK, write DFU application file size (4 bytes), data in %i byte chunks, CRC-32 (4 bytes)",
-	      DFU_UPLOAD_CHUNK_SIZE);
-
-    /* Read file size (4 bytes) */
-    uart_receive_bytes(STM_UART_MGMT, (void *) &filesize, 4, 1000);
-    cli_print(cli, "File size %li, will write it to 0x%lx", filesize, offset);
-
-    HAL_FLASH_Unlock();
-
-    while (filesize) {
-	/* By initializing buf to the same value that erased flash has (0xff), we don't
-	 * have to try and be smart when writing the last page of data to the memory.
-	 */
-	memset(buf, 0xffffffff, sizeof(buf));
-
-	if (filesize < n) {
-	    n = filesize;
-	}
-
-	if (uart_receive_bytes(STM_UART_MGMT, (void *) &buf, n, 1000) != HAL_OK) {
-	    cli_print(cli, "Receive timed out");
-	    return CLI_ERROR;
-	}
-	filesize -= n;
-
-	/* After reception of a chunk but before ACKing we have "all" the time in the world to
-	 * calculate CRC and write it to flash.
-	 */
-	my_crc = update_crc(my_crc, (uint8_t *) buf, n);
-	_write_to_flash(offset, buf, sizeof(buf) / 4);
-	offset += DFU_UPLOAD_CHUNK_SIZE;
-
-	/* ACK this chunk by sending the current chunk counter (4 bytes) */
-	counter++;
-	uart_send_bytes(STM_UART_MGMT, (void *) &counter, 4);
-    }
+__IO uint32_t *dfu_firmware = &CRYPTECH_FIRMWARE_START;
+__IO uint32_t *dfu_firmware_end = &CRYPTECH_FIRMWARE_END;
+/* The first word in the firmware is an address to the stack (msp) */
+__IO uint32_t *dfu_msp_ptr = &CRYPTECH_FIRMWARE_START;
+/* The second word in the firmware is a pointer to the code
+ * (points at the Reset_Handler from the linker script).
+ */
+__IO uint32_t *dfu_code_ptr = &CRYPTECH_FIRMWARE_START + 1;
 
-    HAL_FLASH_Lock();
 
-    /* The sending side will now send it's calculated CRC-32 */
-    cli_print(cli, "Send CRC-32");
-    uart_receive_bytes(STM_UART_MGMT, (void *) &crc, 4, 1000);
-    cli_print(cli, "CRC-32 %li", crc);
-    if (crc == my_crc) {
-	cli_print(cli, "CRC checksum MATCHED");
-    } else {
-	cli_print(cli, "CRC checksum did NOT match");
-    }
-
-    return CLI_OK;
-}
 
 int cmd_dfu_dump(struct cli_def *cli, const char *command, char *argv[], int argc)
 {
-    cli_print(cli, "First 256 bytes from DFU application address %p:\r\n", DFU_FIRMWARE_PTR);
+    cli_print(cli, "First 256 bytes from DFU application address %p:\r\n", dfu_firmware);
 
-    uart_send_hexdump(STM_UART_MGMT, (uint8_t *) DFU_FIRMWARE_ADDR, 0, 0xff);
+    uart_send_hexdump(STM_UART_MGMT, (uint8_t *) dfu_firmware, 0, 0xff);
     uart_send_string2(STM_UART_MGMT, (char *) "\r\n\r\n");
 
     return CLI_OK;
@@ -224,37 +67,18 @@ int cmd_dfu_dump(struct cli_def *cli, const char *command, char *argv[], int arg
 
 int cmd_dfu_erase(struct cli_def *cli, const char *command, char *argv[], int argc)
 {
-    uint32_t start_sector = _flash_sector_num(DFU_FIRMWARE_ADDR);
-    uint32_t end_sector = _flash_sector_num(DFU_FIRMWARE_END_ADDR);
-    uint32_t sector;
+    int status;
 
-    cli_print(cli, "Erasing flash sectors %li to %li (address %p to %p)",
-	      start_sector, end_sector,
-	      (uint32_t *) DFU_FIRMWARE_ADDR,
-	      (uint32_t *) DFU_FIRMWARE_END_ADDR);
+    cli_print(cli, "Erasing flash sectors %i to %i (address %p to %p) - expect the CLI to crash now",
+	      stm_flash_sector_num((uint32_t) dfu_firmware),
+	      stm_flash_sector_num((uint32_t) dfu_firmware_end),
+	      dfu_firmware,
+	      dfu_firmware_end);
 
-    if (start_sector > end_sector) {
-	cli_print(cli, "ERROR: Bad sectors");
-	return CLI_ERROR;
+    if ((status = stm_flash_erase_sectors((uint32_t) dfu_firmware, (uint32_t) dfu_firmware_end)) != 0) {
+	cli_print(cli, "Failed erasing flash sectors (%i)", status);
     }
 
-    HAL_FLASH_Unlock();
-
-    for (sector = start_sector; sector <= end_sector; sector++) {
-	uint32_t SectorError = 0;
-	FLASH_EraseInitTypeDef FLASH_EraseInitStruct;
-
-	FLASH_EraseInitStruct.TypeErase = TYPEERASE_SECTORS;
-	FLASH_EraseInitStruct.Sector = sector;
-	FLASH_EraseInitStruct.NbSectors = 1;
-	FLASH_EraseInitStruct.VoltageRange = VOLTAGE_RANGE_3;
-
-	if (HAL_FLASHEx_Erase(&FLASH_EraseInitStruct, &SectorError) != HAL_OK) {
-	    cli_print(cli, "ERROR: Failed erasing sector %li", sector);
-	}
-    }
-    HAL_FLASH_Lock();
-
     return CLI_OK;
 }
 
@@ -264,21 +88,23 @@ int cmd_dfu_jump(struct cli_def *cli, const char *command, char *argv[], int arg
     /* Load first byte from the DFU_FIRMWARE_PTR to verify it contains an IVT before
      * jumping there.
      */
-    cli_print(cli, "Checking for application at %p", DFU_FIRMWARE_PTR);
+    cli_print(cli, "Checking for application at %p", dfu_firmware);
 
-    //new_msp = (uint32_t) DFU_FIRMWARE_PTR;
-    i = *dfu_new_msp & 0xFF000000;
+    i = *dfu_msp_ptr & 0xFF000000;
     /* 'new_msp' is supposed to be a pointer to the new applications stack, it should
      * point either at RAM (0x20000000) or at the CCM memory (0x10000000).
      */
     if (i == 0x20000000 || i == 0x10000000) {
+	/* Set dfu_control to the magic value that will cause the us to jump to the
+	 * firmware from the CLI main() function after rebooting.
+	 */
 	*dfu_control = HARDWARE_EARLY_DFU_JUMP;
 	cli_print(cli, "Making the leap");
 	HAL_NVIC_SystemReset();
 	while (1) { ; }
     } else {
 	cli_print(cli, "No loaded application found at %p (read 0x%x)",
-		  DFU_FIRMWARE_PTR, (unsigned int) *dfu_new_msp);
+		  dfu_firmware, (unsigned int) *dfu_msp_ptr);
     }
 
     return CLI_OK;
@@ -288,8 +114,7 @@ void configure_cli_dfu(struct cli_def *cli)
 {
     cli_command_root(dfu);
 
-    cli_command_node(dfu, dump, "Show the first 256 bytes of the loaded application");
-    cli_command_node(dfu, jump, "Jump to the loaded application");
-    cli_command_node(dfu, upload, "Load a new application");
-    cli_command_node(dfu, erase, "Erase the application memory");
+    cli_command_node(dfu, dump, "Show the first 256 bytes of the loaded firmware");
+    cli_command_node(dfu, jump, "Jump to the loaded firmware");
+    cli_command_node(dfu, erase, "Erase the firmware memory (will crash the CLI)");
 }
diff --git a/projects/cli-test/mgmt-dfu.h b/projects/cli-test/mgmt-dfu.h
index e1e3932..ac6589c 100644
--- a/projects/cli-test/mgmt-dfu.h
+++ b/projects/cli-test/mgmt-dfu.h
@@ -38,9 +38,22 @@
 #include "stm-init.h"
 #include <libcli.h>
 
-#define DFU_UPLOAD_CHUNK_SIZE 256
+/* symbols defined in the linker script (STM32F429BI.ld) */
+extern uint32_t CRYPTECH_FIRMWARE_START;
+extern uint32_t CRYPTECH_FIRMWARE_END;
+extern uint32_t CRYPTECH_DFU_CONTROL;
+
+#define DFU_FIRMWARE_ADDR         ((uint32_t) &CRYPTECH_FIRMWARE_START)
+#define DFU_FIRMWARE_END_ADDR     ((uint32_t) &CRYPTECH_FIRMWARE_END)
+#define DFU_UPLOAD_CHUNK_SIZE     256
+#define HARDWARE_EARLY_DFU_JUMP   0xBADABADA
+
+extern __IO uint32_t *dfu_control;
+extern __IO uint32_t *dfu_firmware;
+extern __IO uint32_t *dfu_msp_ptr;
+extern __IO uint32_t *dfu_code_ptr;
+
 
 extern void configure_cli_dfu(struct cli_def *cli);
-extern void check_early_dfu_jump(void);
 
 #endif /* __STM32_CLI_MGMT_DFU_H */
diff --git a/stm-flash.c b/stm-flash.c
new file mode 100644
index 0000000..991379b
--- /dev/null
+++ b/stm-flash.c
@@ -0,0 +1,138 @@
+/*
+ * stm-flash.c
+ * -----------
+ * Functions for writing/erasing the STM32 internal flash memory.
+ * The flash is memory mapped, so no code is needed here to read it.
+ *
+ * Copyright (c) 2016, NORDUnet A/S All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of the NORDUnet nor the names of its contributors may
+ *   be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "stm32f4xx_hal.h"
+#include "stm-flash.h"
+#include "stm-init.h"
+
+
+/* Flash sector offsets from RM0090, Table 6. Flash module - 2 Mbyte dual bank organization */
+#define FLASH_NUM_SECTORS 24
+uint32_t flash_sector_offsets[FLASH_NUM_SECTORS + 1] = {
+    /* Bank 1 */
+    0x08000000, /* #0,  16 KBytes */
+    0x08004000, /* #1,  16 Kbytes */
+    0x08008000, /* #2,  16 Kbytes */
+    0x0800C000, /* #3,  16 Kbytes */
+    0x08010000, /* #4,  64 Kbytes */
+    0x08020000, /* #5,  128 Kbytes */
+    0x08040000, /* #6,  128 Kbytes */
+    0x08060000, /* #7,  128 Kbytes */
+    0x08080000, /* #8,  128 Kbytes */
+    0x080A0000, /* #9,  128 Kbytes */
+    0x080C0000, /* #10, 128 Kbytes */
+    0x080E0000, /* #11, 128 Kbytes */
+    /* Bank 2 */
+    0x08100000, /* #12,  16 Kbytes */
+    0x08104000, /* #13,  16 Kbytes */
+    0x08108000, /* #14,  16 Kbytes */
+    0x0810C000, /* #15,  16 Kbytes */
+    0x08110000, /* #16,  64 Kbytes */
+    0x08120000, /* #17, 128 Kbytes */
+    0x08140000, /* #18, 128 Kbytes */
+    0x08160000, /* #19, 128 Kbytes */
+    0x08180000, /* #20, 128 Kbytes */
+    0x081A0000, /* #21, 128 Kbytes */
+    0x081C0000, /* #22, 128 Kbytes */
+    0x081E0000, /* #23, 128 Kbytes */
+    0x08200000  /* first address *after* flash */
+};
+
+int stm_flash_sector_num(const uint32_t offset)
+{
+    int i = FLASH_NUM_SECTORS;
+
+    while (i-- >= 0) {
+	if (offset >= flash_sector_offsets[i] &&
+	    offset < flash_sector_offsets[i + 1]) {
+	    return i;
+	}
+    }
+    return -1;
+}
+
+int stm_flash_erase_sectors(const uint32_t start_offset, const uint32_t end_offset)
+{
+    uint32_t start_sector = stm_flash_sector_num(start_offset);
+    uint32_t end_sector = stm_flash_sector_num(end_offset);
+    FLASH_EraseInitTypeDef FLASH_EraseInitStruct;
+    uint32_t SectorError = 0;
+
+    if (start_sector > end_sector) return -1;
+    if (start_sector < 0 || end_sector > FLASH_NUM_SECTORS) return -2;
+
+    FLASH_EraseInitStruct.Sector = start_sector;
+    FLASH_EraseInitStruct.NbSectors = (end_sector - start_sector) + 1;
+    FLASH_EraseInitStruct.TypeErase = TYPEERASE_SECTORS;
+    FLASH_EraseInitStruct.VoltageRange = VOLTAGE_RANGE_3;
+
+    HAL_FLASH_Unlock();
+
+    if (HAL_FLASHEx_Erase(&FLASH_EraseInitStruct, &SectorError) != HAL_OK) {
+	return -3;
+    }
+
+    HAL_FLASH_Lock();
+
+    if (SectorError == 0xFFFFFFFF) return 0;
+
+    return -3;
+}
+
+int stm_flash_write32(uint32_t offset, const uint32_t *buf, const uint32_t elements)
+{
+    uint32_t sector = stm_flash_sector_num(offset);
+    uint32_t i, j;
+
+    if (offset == flash_sector_offsets[sector]) {
+	/* Request to write to beginning of a flash sector, erase it first. */
+	if (stm_flash_erase_sectors(offset, offset) != 0) {
+	    return -1;
+	}
+    }
+
+    HAL_FLASH_Unlock();
+
+    for (i = 0; i < elements; i++) {
+	if ((j = HAL_FLASH_Program(FLASH_TYPEPROGRAM_WORD, offset, buf[i])) != HAL_OK) {
+	    return -2;
+	}
+	offset += 4;
+    }
+
+    HAL_FLASH_Lock();
+
+    return 1;
+}
diff --git a/stm-flash.h b/stm-flash.h
new file mode 100644
index 0000000..a9cf7db
--- /dev/null
+++ b/stm-flash.h
@@ -0,0 +1,42 @@
+/*
+ * stm-flash.h
+ * -----------
+ * Functions and defines for accessing the flash memory.
+ *
+ * Copyright (c) 2016, NORDUnet A/S All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of the NORDUnet nor the names of its contributors may
+ *   be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __STM32_FLASH_H
+#define __STM32_FLASH_H
+
+extern int stm_flash_sector_num(const uint32_t offset);
+extern int stm_flash_erase_sectors(const uint32_t start_offset, const uint32_t end_offset);
+extern int stm_flash_write32(const uint32_t offset, const uint32_t *buf, const uint32_t elements);
+
+#endif /* __STM32_FLASH_H */