1 files changed, 975 insertions, 0 deletions

diff --git a/utils/sansapatcher/sansapatcher.c b/utils/sansapatcher/sansapatcher.c
new file mode 100644
index 0000000000..e3b105dcca
--- /dev/null
+++ b/utils/sansapatcher/sansapatcher.c
@@ -0,0 +1,975 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2006-2007 Dave Chapman
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "sansaio.h"
+#include "sansapatcher.h"
+
+/* The offset of the MI4 image header in the firmware partition */
+#define PPMI_OFFSET     0x80000
+#define NVPARAMS_OFFSET 0x780000
+#define NVPARAMS_SIZE   (0x80000-0x200)
+
+int sansa_verbose = 0;
+
+/* Windows requires the buffer for disk I/O to be aligned in memory on a
+   multiple of the disk volume size - so we use a single global variable
+   and initialise it with sansa_alloc_buf() in main().
+*/
+
+static off_t filesize(int fd) {
+    struct stat buf;
+
+    if (fstat(fd,&buf) < 0) {
+        perror("[ERR]  Checking filesize of input file");
+        return -1;
+    } else {
+        return(buf.st_size);
+    }
+}
+
+/* Partition table parsing code taken from Rockbox */
+
+#define MAX_SECTOR_SIZE 2048
+#define SECTOR_SIZE 512
+
+static inline int32_t le2int(const unsigned char* buf)
+{
+   int32_t res = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+
+   return res;
+}
+
+static inline uint32_t le2uint(const unsigned char* buf)
+{
+   uint32_t res = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+
+   return res;
+}
+
+static inline void int2le(unsigned int val, unsigned char* addr)
+{
+    addr[0] = val & 0xFF;
+    addr[1] = (val >> 8) & 0xff;
+    addr[2] = (val >> 16) & 0xff;
+    addr[3] = (val >> 24) & 0xff;
+}
+
+#define BYTES2INT32(array,pos)\
+    ((long)array[pos] | ((long)array[pos+1] << 8 ) |\
+    ((long)array[pos+2] << 16 ) | ((long)array[pos+3] << 24 ))
+
+int sansa_read_partinfo(struct sansa_t* sansa, int silent)
+{
+    int i;
+    unsigned long count;
+
+    count = sansa_read(sansa,sansa->sectorbuf, sansa->sector_size);
+
+    if (count <= 0) {
+        sansa_print_error(" Error reading from disk: ");
+        return -1;
+    }
+
+    if ((sansa->sectorbuf[510] == 0x55) && (sansa->sectorbuf[511] == 0xaa)) {
+        /* parse partitions */
+        for ( i = 0; i < 4; i++ ) {
+            unsigned char* ptr = sansa->sectorbuf + 0x1be + 16*i;
+            sansa->pinfo[i].type  = ptr[4];
+            sansa->pinfo[i].start = BYTES2INT32(ptr, 8);
+            sansa->pinfo[i].size  = BYTES2INT32(ptr, 12);
+
+            /* extended? */
+            if ( sansa->pinfo[i].type == 5 ) {
+                /* not handled yet */
+            }
+        }
+    } else if ((sansa->sectorbuf[0] == 'E') && (sansa->sectorbuf[1] == 'R')) {
+        if (!silent) fprintf(stderr,"[ERR]  Bad boot sector signature\n");
+        return -1;
+    }
+
+    /* Calculate the starting position of the firmware partition */
+    sansa->start = (loff_t)sansa->pinfo[1].start*(loff_t)sansa->sector_size;
+    return 0;
+}
+
+/* NOTE: memmem implementation copied from glibc-2.2.4 - it's a GNU
+   extension and is not universally.  In addition, early versions of
+   memmem had a serious bug - the meaning of needle and haystack were
+   reversed. */
+
+/* Copyright (C) 1991,92,93,94,96,97,98,2000 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+/* Return the first occurrence of NEEDLE in HAYSTACK.  */
+static void *
+sansa_memmem (haystack, haystack_len, needle, needle_len)
+     const void *haystack;
+     size_t haystack_len;
+     const void *needle;
+     size_t needle_len;
+{
+  const char *begin;
+  const char *const last_possible
+    = (const char *) haystack + haystack_len - needle_len;
+
+  if (needle_len == 0)
+    /* The first occurrence of the empty string is deemed to occur at
+       the beginning of the string.  */
+    return (void *) haystack;
+
+  /* Sanity check, otherwise the loop might search through the whole
+     memory.  */
+  if (__builtin_expect (haystack_len < needle_len, 0))
+    return NULL;
+
+  for (begin = (const char *) haystack; begin <= last_possible; ++begin)
+    if (begin[0] == ((const char *) needle)[0] &&
+        !memcmp ((const void *) &begin[1],
+                 (const void *) ((const char *) needle + 1),
+                 needle_len - 1))
+        return (void *) begin;
+
+  return NULL;
+}
+
+/*
+ * CRC32 implementation taken from:
+ *
+ * efone - Distributed internet phone system.
+ *
+ * (c) 1999,2000 Krzysztof Dabrowski
+ * (c) 1999,2000 ElysiuM deeZine
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+/* crc_tab[] -- this crcTable is being build by chksum_crc32GenTab().
+ *              so make sure, you call it before using the other
+ *              functions!
+ */
+static unsigned int crc_tab[256];
+
+/* chksum_crc() -- to a given block, this one calculates the
+ *                 crc32-checksum until the length is
+ *                 reached. the crc32-checksum will be
+ *                 the result.
+ */
+static unsigned int chksum_crc32 (const unsigned char *block, unsigned int length)
+{
+   register unsigned long crc;
+   unsigned long i;
+
+   crc = 0;
+   for (i = 0; i < length; i++)
+   {
+      crc = ((crc >> 8) & 0x00FFFFFF) ^ crc_tab[(crc ^ *block++) & 0xFF];
+   }
+   return (crc);
+}
+
+/* chksum_crc32gentab() --      to a global crc_tab[256], this one will
+ *                              calculate the crcTable for crc32-checksums.
+ *                              it is generated to the polynom [..]
+ */
+
+static void chksum_crc32gentab (void)
+{
+    unsigned long crc, poly;
+    int i, j;
+
+    poly = 0xEDB88320L;
+    for (i = 0; i < 256; i++)
+    {
+        crc = i;
+        for (j = 8; j > 0; j--)
+        {
+            if (crc & 1)
+            {
+                crc = (crc >> 1) ^ poly;
+            }
+            else
+            {
+                crc >>= 1;
+            }
+        }
+        crc_tab[i] = crc;
+    }
+}
+
+/* Known keys for Sansa E200 and C200 firmwares: */
+#define NUM_KEYS ((int)(sizeof(keys)/sizeof(keys[0])))
+static const uint32_t keys[][4] = {
+    { 0xe494e96e, 0x3ee32966, 0x6f48512b, 0xa93fbb42 }, /* "sansa" */
+    { 0xd7b10538, 0xc662945b, 0x1b3fce68, 0xf389c0e6 }, /* "sansa_gh" */
+    { 0x1d29ddc0, 0x2579c2cd, 0xce339e1a, 0x75465dfe }, /* sansa 103 */
+    
+    { 0x2a7968de, 0x15127979, 0x142e60a7, 0xe49c1893 }, /* c200 1.00.03 */
+    { 0xbf2d06fa, 0xf0e23d59, 0x29738132, 0xe2d04ca7 }, /* c200 1.00.04 and up*/
+    { 0xa913d139, 0xf842f398, 0x3e03f1a6, 0x060ee012 }, /* c200 1.01.05 and up*/
+    { 0x0fe92902, 0xe8cc0f89, 0x6ff568ba, 0x1eff5161 }, /* c200 1.01.07 */
+};
+
+/*
+
+tea_decrypt() from http://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm
+
+"Following is an adaptation of the reference encryption and decryption
+routines in C, released into the public domain by David Wheeler and
+Roger Needham:"
+
+*/
+
+/* NOTE: The mi4 version of TEA uses a different initial value to sum compared
+         to the reference implementation and the main loop is 8 iterations, not
+         32.
+*/
+
+static void tea_decrypt(uint32_t* v0, uint32_t* v1, const uint32_t* k) {
+    uint32_t sum=0xF1BBCDC8, i;                    /* set up */
+    uint32_t delta=0x9E3779B9;                     /* a key schedule constant */
+    uint32_t k0=k[0], k1=k[1], k2=k[2], k3=k[3];   /* cache key */
+    for(i=0; i<8; i++) {                               /* basic cycle start */
+        *v1 -= ((*v0<<4) + k2) ^ (*v0 + sum) ^ ((*v0>>5) + k3);
+        *v0 -= ((*v1<<4) + k0) ^ (*v1 + sum) ^ ((*v1>>5) + k1);
+        sum -= delta;                                   /* end cycle */
+    }
+}
+
+/* mi4 files are encrypted in 64-bit blocks (two little-endian 32-bit
+   integers) and the key is incremented after each block
+ */
+
+static void tea_decrypt_buf(const unsigned char* src, unsigned char* dest,
+                            size_t n, const uint32_t * initial_key)
+{
+    uint32_t v0, v1;
+    unsigned int i;
+    uint32_t key[4];
+
+    memcpy(key, initial_key, sizeof(key));
+    for (i = 0; i < (n / 8); i++) {
+        v0 = le2int(src);
+        v1 = le2int(src+4);
+
+        tea_decrypt(&v0, &v1, key);
+
+        int2le(v0, dest);
+        int2le(v1, dest+4);
+
+        src += 8;
+        dest += 8;
+
+        /* Now increment the key */
+        key[0]++;
+        if (key[0]==0) {
+            key[1]++;
+            if (key[1]==0) {
+                key[2]++;
+                if (key[2]==0) {
+                    key[3]++;
+                }
+            }
+        }
+    }
+}
+
+static int get_mi4header(const unsigned char* buf,struct mi4header_t* mi4header)
+{
+    if (memcmp(buf,"PPOS",4)!=0)
+        return -1;
+
+    mi4header->version   = le2int(buf+0x04);
+    mi4header->length    = le2int(buf+0x08);
+    mi4header->crc32     = le2int(buf+0x0c);
+    mi4header->enctype   = le2int(buf+0x10);
+    mi4header->mi4size   = le2int(buf+0x14);
+    mi4header->plaintext = le2int(buf+0x18);
+
+    return 0;
+}
+
+static int set_mi4header(unsigned char* buf,const struct mi4header_t* mi4header)
+{
+    if (memcmp(buf,"PPOS",4)!=0)
+        return -1;
+
+    int2le(mi4header->version   ,buf+0x04);
+    int2le(mi4header->length    ,buf+0x08);
+    int2le(mi4header->crc32     ,buf+0x0c);
+    int2le(mi4header->enctype   ,buf+0x10);
+    int2le(mi4header->mi4size   ,buf+0x14);
+    int2le(mi4header->plaintext ,buf+0x18);
+
+    /* Add a dummy DSA signature */
+    memset(buf+0x1c,0,40);
+    buf[0x2f] = 1;
+
+    return 0;
+}
+
+static int sansa_seek_and_read(struct sansa_t* sansa, loff_t pos, unsigned char* buf, int nbytes)
+{
+    int n;
+
+    if (sansa_seek(sansa, pos) < 0) {
+        return -1;
+    }
+
+    if ((n = sansa_read(sansa,buf,nbytes)) < 0) {
+        return -1;
+    }
+
+    if (n < nbytes) {
+        fprintf(stderr,"[ERR]  Short read - requested %d bytes, received %d\n",
+                nbytes,n);
+        return -1;
+    }
+
+    return 0;
+}
+
+
+/* We identify an E200 based on the following criteria:
+
+   1) Exactly two partitions;
+   2) First partition is type "W95 FAT32" (0x0b or 0x0c);
+   3) Second partition is type "OS/2 hidden C: drive" (0x84);
+   4) The "PPBL" string appears at offset 0 in the 2nd partition;
+   5) The "PPMI" string appears at offset PPMI_OFFSET in the 2nd partition.
+*/
+
+int is_sansa(struct sansa_t* sansa)
+{
+    struct mi4header_t mi4header;
+    int ppmi_length;
+    int ppbl_length;
+
+    /* Check partition layout */
+    if (((sansa->pinfo[0].type != 0x06) &&
+         (sansa->pinfo[0].type != 0x0b) &&
+         (sansa->pinfo[0].type != 0x0c) &&
+         (sansa->pinfo[0].type != 0x0e)) ||
+        (sansa->pinfo[1].type != 0x84) ||
+        (sansa->pinfo[2].type != 0x00) || 
+        (sansa->pinfo[3].type != 0x00)) {
+        /* Bad partition layout, abort */
+        return -1;
+    }
+
+    /* Check Bootloader header */
+    if (sansa_seek_and_read(sansa, sansa->start, sansa->sectorbuf, 0x200) < 0) {
+        return -2;
+    }
+    if (memcmp(sansa->sectorbuf,"PPBL",4)!=0) {
+        /* No bootloader header, abort */
+        return -4;
+    }
+    ppbl_length = (le2int(sansa->sectorbuf+4) + 0x1ff) & ~0x1ff;
+
+    /* Sanity/safety check - the bootloader can't be larger than PPMI_OFFSET */
+    if (ppbl_length > PPMI_OFFSET)
+    {
+        return -5;
+    }
+
+    /* Load Sansa bootloader and check for "Sansa C200" magic string */
+    if (sansa_seek_and_read(sansa, sansa->start + 0x200, sansa->sectorbuf, ppbl_length) < 0) {
+        fprintf(stderr,"[ERR]  Seek and read to 0x%08"PRIx64" in is_sansa failed.\n",
+                       sansa->start+0x200);
+        return -6;
+    }
+    if (sansa_memmem(sansa->sectorbuf, ppbl_length, "Sansa C200", 10) != NULL) {
+        /* C200 */
+        sansa->targetname="c200";
+    } else {
+        /* E200 */
+        sansa->targetname="e200";
+    }
+
+    /* Check Main firmware header */
+    if (sansa_seek_and_read(sansa, sansa->start+PPMI_OFFSET, sansa->sectorbuf, 0x200) < 0) {
+        fprintf(stderr,"[ERR]  Seek to 0x%"PRIx64" in is_sansa failed.\n",
+                       sansa->start+PPMI_OFFSET);
+        return -5;
+    }
+    if (memcmp(sansa->sectorbuf,"PPMI",4)!=0) {
+        /* No bootloader header, abort */
+        return -7;
+    }
+    ppmi_length = le2int(sansa->sectorbuf+4);
+
+    /* Check main mi4 file header */
+    if (sansa_seek_and_read(sansa, sansa->start+PPMI_OFFSET+0x200, sansa->sectorbuf, 0x200) < 0) {
+        fprintf(stderr,"[ERR]  Seek to 0x%"PRIx64" in is_sansa failed.\n",
+                       sansa->start+PPMI_OFFSET+0x200);
+        return -5;
+    }
+
+    if (get_mi4header(sansa->sectorbuf,&mi4header) < 0) {
+        fprintf(stderr,"[ERR]  Invalid mi4header\n");
+        return -6;
+    }
+
+    /* Some sanity checks:
+
+       1) Main MI4 image without RBBL and < 100000 bytes -> old install
+       2) Main MI4 image with RBBL but no second image -> old install
+     */
+
+    sansa->hasoldbootloader = 0;
+    if (memcmp(sansa->sectorbuf+0x1f8,"RBBL",4)==0) {
+        /* Look for an original firmware after the first image */
+        if (sansa_seek_and_read(sansa,
+                                sansa->start + PPMI_OFFSET + 0x200 + ppmi_length,
+                                sansa->sectorbuf, 512) < 0) {
+            return -7;
+        }
+
+        if (get_mi4header(sansa->sectorbuf,&mi4header)!=0) {
+            fprintf(stderr,"[ERR]  No original firmware found\n");
+            sansa->hasoldbootloader = 1;
+        }
+    } else if (mi4header.mi4size < 100000) {
+        fprintf(stderr,"[ERR]  Old bootloader found\n");
+        sansa->hasoldbootloader = 1;
+    }
+
+    return 0;
+}
+
+int sansa_scan(struct sansa_t* sansa)
+{
+    int i;
+    int n = 0;
+    char last_disk[4096];
+    int denied = 0;
+    int result;
+
+    printf("[INFO] Scanning disk devices...\n");
+
+    for (i = 0; i <= 25 ; i++) {
+#ifdef __WIN32__
+        sprintf(sansa->diskname,"\\\\.\\PhysicalDrive%d",i);
+#elif defined(linux) || defined (__linux)
+        sprintf(sansa->diskname,"/dev/sd%c",'a'+i);
+#elif defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) \
+        || defined(__bsdi__) || defined(__DragonFly__)
+        sprintf(sansa->diskname,"/dev/da%d",i);
+#elif defined(__APPLE__) && defined(__MACH__)
+        sprintf(sansa->diskname,"/dev/disk%d",i);
+#else
+#error No disk paths defined for this platform
+#endif
+        if ((result = sansa_open(sansa, 1)) < 0) {
+            if(result == -2) {
+                denied++;
+            }
+            sansa_close(sansa);
+            continue;
+        }
+
+        if (sansa_read_partinfo(sansa,1) < 0) {
+            sansa_close(sansa);
+            continue;
+        }
+
+        if (is_sansa(sansa) < 0) {
+            sansa_close(sansa);
+            continue;
+        }
+
+#ifdef __WIN32__
+        printf("[INFO] %s found - disk device %d\n",sansa->targetname, i);
+#else
+        printf("[INFO] %s found - %s\n",sansa->targetname, sansa->diskname);
+#endif
+        n++;
+        strcpy(last_disk,sansa->diskname);
+        sansa_close(sansa);
+    }
+
+    if (n==1) {
+        /* Remember the disk name */
+        strcpy(sansa->diskname,last_disk);
+    }
+    else if (n == 0 && denied) {
+        printf("[ERR]  FATAL: Permission denied on %d device(s) and no sansa detected.\n", denied);
+#ifdef __WIN32__
+        printf("[ERR]  You need to run this program with administrator priviledges!\n");
+#else
+        printf("[ERR]  You need permissions for raw disc access for this program to work!\n");
+#endif
+    }
+
+    return (n == 0 && denied) ? -1 : n;
+}
+
+/* Prepare original firmware for writing to the firmware partition by decrypting
+   and updating the header */
+static int prepare_original_firmware(struct sansa_t* sansa, unsigned char* buf, struct mi4header_t* mi4header)
+{
+    unsigned char* tmpbuf;
+    int i;
+    int key_found;
+
+    get_mi4header(buf,mi4header);
+
+#if 0
+    printf("mi4header->version   =0x%08x\n",mi4header->version);
+    printf("mi4header->length    =0x%08x\n",mi4header->length);
+    printf("mi4header->crc32     =0x%08x\n",mi4header->crc32);
+    printf("mi4header->enctype   =0x%08x\n",mi4header->enctype);
+    printf("mi4header->mi4size   =0x%08x\n",mi4header->mi4size);
+    printf("mi4header->plaintext =0x%08x\n",mi4header->plaintext);
+#endif
+
+    /* Decrypt anything that needs decrypting. */
+    if (mi4header->plaintext < mi4header->mi4size - 0x200) {
+        /* TODO: Check different keys */
+        tmpbuf=malloc(mi4header->mi4size-(mi4header->plaintext+0x200));
+        if (tmpbuf==NULL) {
+            fprintf(stderr,"[ERR]  Can not allocate memory\n");
+            return -1;
+        }
+
+        key_found=0;
+        for (i=0; i < NUM_KEYS && !key_found ; i++) {
+            tea_decrypt_buf(buf+(mi4header->plaintext+0x200),
+                            tmpbuf,
+                            mi4header->mi4size-(mi4header->plaintext+0x200),
+                            keys[i]);
+            key_found = (le2uint(tmpbuf+mi4header->length-mi4header->plaintext-4) == 0xaa55aa55);
+        }
+
+        if (key_found) {
+            memcpy(buf+(mi4header->plaintext+0x200),tmpbuf,mi4header->mi4size-(mi4header->plaintext+0x200));
+            free(tmpbuf);
+        } else {
+            fprintf(stderr,"[ERR]  Failed to decrypt image, aborting\n");
+            free(tmpbuf);
+            return -1;
+        }
+    }
+
+    /* Increase plaintext value to full file */
+    mi4header->plaintext = mi4header->mi4size - 0x200;
+
+    /* Update CRC checksum */
+    chksum_crc32gentab ();
+    mi4header->crc32 = chksum_crc32(buf+0x200,mi4header->mi4size-0x200);
+
+    set_mi4header(buf,mi4header);
+
+    /* Add Rockbox-specific header */
+    memcpy(buf+0x1f8,"RBOF",4);
+    memcpy(buf+0x1fc,sansa->targetname,4);
+
+    return 0;
+}
+
+static int load_original_firmware(struct sansa_t* sansa, unsigned char* buf, struct mi4header_t* mi4header)
+{
+    int ppmi_length;
+    int n;
+    
+    /* Read 512 bytes from PPMI_OFFSET - the PPMI header plus the mi4 header */
+    if (sansa_seek_and_read(sansa, sansa->start + PPMI_OFFSET, buf, 512) < 0) {
+        return -1;
+    }
+
+    /* No need to check PPMI magic - it's done during init to confirm
+       this is an E200 */
+    ppmi_length = le2int(buf+4);
+
+    /* Firstly look for an original firmware after the first image */
+    if (sansa_seek_and_read(sansa, sansa->start + PPMI_OFFSET + 0x200 + ppmi_length, buf, 512) < 0) {
+        return -1;
+    }
+
+    if (get_mi4header(buf,mi4header)==0) {
+        /* We have a valid MI4 file after a bootloader, so we use this. */
+        if ((n = sansa_seek_and_read(sansa,
+                                     sansa->start + PPMI_OFFSET + 0x200 + ppmi_length,
+                                     buf, mi4header->mi4size)) < 0) {
+            return -1;
+        }
+    } else {
+        /* No valid MI4 file, so read the first image. */
+        if ((n = sansa_seek_and_read(sansa,
+                                     sansa->start + PPMI_OFFSET + 0x200,
+                                     buf, ppmi_length)) < 0) {
+            return -1;
+        }
+    }
+    return prepare_original_firmware(sansa, buf, mi4header);
+}
+
+int sansa_read_firmware(struct sansa_t* sansa, const char* filename)
+{
+    int res;
+    int outfile;
+    struct mi4header_t mi4header;
+
+    res = load_original_firmware(sansa,sansa->sectorbuf,&mi4header);
+    if (res < 0)
+        return res;
+
+    outfile = open(filename,O_CREAT|O_TRUNC|O_WRONLY|O_BINARY,0666);
+    if (outfile < 0) {
+        fprintf(stderr,"[ERR]  Couldn't open file %s\n",filename);
+        return -1;
+    }
+
+    res = write(outfile,sansa->sectorbuf,mi4header.mi4size);
+    if (res != (int)mi4header.mi4size) {
+        fprintf(stderr,"[ERR]  Write error - %d\n", res);
+        return -1;
+    }
+    close(outfile);
+
+    return 0;
+}
+
+unsigned int sansa_read_bootloader(struct sansa_t* sansa, const char* filename, unsigned char** bl_buffer)
+{
+    /* Step 1 - read bootloader into RAM. */
+    int infile;
+    unsigned int n;
+    unsigned int len;
+    infile=open(filename,O_RDONLY|O_BINARY);
+    if (infile < 0) {
+        fprintf(stderr,"[ERR]  Couldn't open input file %s\n",filename);
+        return 0;
+    }
+
+    len = filesize(infile);
+
+    unsigned char* b = malloc(len);
+    if (b == NULL) {
+        fprintf(stderr,"[ERR]  Could not allocate memory for bootloader\n");
+        close(infile);
+        return 0;
+    }
+
+    n = read(infile,b,len);
+    close(infile);
+    if (n < len) {
+        fprintf(stderr,"[ERR]  Short read - requested %d bytes, received %d\n"
+                ,len,n);
+        return 0;
+    }
+
+    if (memcmp(b+0x1f8,"RBBL",4)!=0) {
+        fprintf(stderr,"[ERR]  %s is not a Rockbox bootloader, aborting.\n",
+                filename);
+        return 0;
+    }
+    if (memcmp(b+0x1fc,sansa->targetname,4)!=0) {
+        fprintf(stderr,"[ERR]  %s is not a Rockbox bootloader for %s, aborting.\n",
+                filename, sansa->targetname);
+        return 0;
+    }
+    *bl_buffer = b;
+    return len;
+}
+
+int sansa_add_bootloader(struct sansa_t* sansa, const unsigned char* bootloader, const unsigned int bl_length)
+{
+    int res;
+    struct mi4header_t mi4header;
+    int length;
+    int n;
+
+    /* Create PPMI header */
+    memset(sansa->sectorbuf,0,0x200);
+    memcpy(sansa->sectorbuf,"PPMI",4);
+    int2le(bl_length,   sansa->sectorbuf+4);
+    int2le(0x00020000,  sansa->sectorbuf+8);
+
+    /* copy bootloader to sansa->sectorbuf+0x200 */
+    memcpy(sansa->sectorbuf+0x200,bootloader,bl_length);
+
+    /* Load original firmware from Sansa to the space after the bootloader */
+    res = load_original_firmware(sansa,sansa->sectorbuf+0x200+bl_length,&mi4header);
+    if (res < 0)
+        return res;
+
+    /* Now write the whole thing back to the Sansa */
+
+    if (sansa_seek(sansa, sansa->start+PPMI_OFFSET) < 0) {
+        fprintf(stderr,"[ERR]  Seek to 0x%08"PRIx64" in add_bootloader failed.\n",
+                       sansa->start+PPMI_OFFSET);
+        return -5;
+    }
+
+    length = 0x200 + bl_length + mi4header.mi4size;
+
+    n=sansa_write(sansa, length);
+    if (n < length) {
+        fprintf(stderr,"[ERR]  Short write in add_bootloader\n");
+        return -6;
+    }
+
+    return 0;
+}
+
+int sansa_delete_bootloader(struct sansa_t* sansa)
+{
+    int res;
+    struct mi4header_t mi4header;
+    int n;
+    int length;
+
+    /* Load original firmware from Sansa to sansa->sectorbuf+0x200 */
+    res = load_original_firmware(sansa,sansa->sectorbuf+0x200,&mi4header);
+    if (res < 0)
+        return res;
+
+    /* Create PPMI header */
+    memset(sansa->sectorbuf,0,0x200);
+    memcpy(sansa->sectorbuf,"PPMI",4);
+    int2le(mi4header.mi4size, sansa->sectorbuf+4);
+    int2le(0x00020000,        sansa->sectorbuf+8);
+
+    /* Now write the whole thing back to the Sansa */
+
+    if (sansa_seek(sansa, sansa->start+PPMI_OFFSET) < 0) {
+        fprintf(stderr,"[ERR]  Seek to 0x%08"PRIx64" in add_bootloader failed.\n",
+                       sansa->start+PPMI_OFFSET);
+        return -5;
+    }
+
+    length = 0x200 + mi4header.mi4size;
+
+    n=sansa_write(sansa, length);
+    if (n < length) {
+        fprintf(stderr,"[ERR]  Short write in delete_bootloader\n");
+        return -6;
+    }
+
+    return 0;
+}
+
+/** List number of MI4 images on the player, return number.
+ */
+int sansa_list_images(struct sansa_t* sansa)
+{
+    struct mi4header_t mi4header;
+    loff_t ppmi_length;
+    int num = 0;
+
+    /* Check Main firmware header */
+    if (sansa_seek_and_read(sansa, sansa->start+PPMI_OFFSET, sansa->sectorbuf, 0x200) < 0) {
+        return 0;
+    }
+
+    ppmi_length = le2int(sansa->sectorbuf+4);
+
+    printf("[INFO] Image 1 - %"PRIu64" bytes\n",ppmi_length);
+    num = 1;
+
+    /* Look for an original firmware after the first image */
+    if (sansa_seek_and_read(sansa, sansa->start + PPMI_OFFSET + 0x200 + ppmi_length, sansa->sectorbuf, 512) < 0) {
+        return 0;
+    }
+
+    if (get_mi4header(sansa->sectorbuf,&mi4header)==0) {
+        printf("[INFO] Image 2 - %d bytes\n",mi4header.mi4size);
+        num = 2;
+    }
+    return num;
+}
+
+int sansa_update_of(struct sansa_t* sansa, const char* filename)
+{
+    int n;
+    int infile = -1;   /* Prevent an erroneous "may be used uninitialised" gcc warning */
+    int of_length = 0; /* Keep gcc happy when building for rbutil */
+    int ppmi_length;
+    struct mi4header_t mi4header;
+    unsigned char buf[512];
+
+    /* Step 1 - check we have an OF on the Sansa to upgrade. We expect the 
+       Rockbox bootloader to be installed and the OF to be after it on disk. */
+
+    /* Read 512 bytes from PPMI_OFFSET - the PPMI header */
+    if (sansa_seek_and_read(sansa, sansa->start + PPMI_OFFSET,
+                            buf, 512) < 0) {
+        return -1;
+    }
+
+    /* No need to check PPMI magic - it's done during init to confirm
+       this is an E200 */
+    ppmi_length = le2int(buf+4);
+
+    /* Look for an original firmware after the first image */
+    if (sansa_seek_and_read(sansa, sansa->start+PPMI_OFFSET+0x200+ppmi_length,
+                            buf, 512) < 0) {
+        return -1;
+    }
+
+    if (get_mi4header(buf,&mi4header)!=0) {
+        /* We don't have a valid MI4 file after a bootloader, so do nothing. */
+        fprintf(stderr,"[ERR]  No original firmware found at 0x%08"PRIx64"\n",
+                    sansa->start+PPMI_OFFSET+0x200+ppmi_length);
+        return -1;
+    }
+
+    /* Step 2 - read OF into RAM. */
+    infile=open(filename,O_RDONLY|O_BINARY);
+    if (infile < 0) {
+        fprintf(stderr,"[ERR]  Couldn't open input file %s\n",filename);
+        return -1;
+    }
+
+    of_length = filesize(infile);
+
+    /* Load original firmware from file */
+    memset(sansa->sectorbuf,0,0x200);
+    n = read(infile,sansa->sectorbuf,of_length);
+    close(infile);
+    if (n < of_length) {
+           fprintf(stderr,"[ERR]  Short read - requested %d bytes, received %d\n"
+                         , of_length, n);
+           return -1;
+    }
+
+    /* Check we have a valid MI4 file. */
+    if (get_mi4header(sansa->sectorbuf,&mi4header)!=0) {
+        fprintf(stderr,"[ERR]  %s is not a valid mi4 file\n",filename);
+        return -1;
+    }
+
+    /* Decrypt and build the header */
+    if(prepare_original_firmware(sansa, sansa->sectorbuf, &mi4header)!=0){
+        fprintf(stderr,"[ERR]  Unable to build decrypted mi4 from %s\n"
+                      ,filename);
+        return -1;
+    }
+
+    /* Step 3 - write the OF to the Sansa */
+    if (sansa_seek(sansa, sansa->start+PPMI_OFFSET+0x200+ppmi_length) < 0) {
+        fprintf(stderr,"[ERR]  Seek to 0x%08"PRIx64" in sansa_update_of failed.\n",
+                   sansa->start+PPMI_OFFSET+0x200+ppmi_length);
+        return -1;
+    }
+
+    n=sansa_write(sansa, of_length);
+    if (n < of_length) {
+        fprintf(stderr,"[ERR]  Short write in sansa_update_of\n");
+        return -1;
+    }
+    
+    /* Step 4 - zero out the nvparams section - we have to do this or we end up
+       with multiple copies of the nvparams data and don't know which one to
+       work with for the database rebuild disabling trick in our bootloader */
+    if (strcmp(sansa->targetname,"e200") == 0) {
+        printf("[INFO] Resetting Original Firmware settings\n");
+        if (sansa_seek(sansa, sansa->start+NVPARAMS_OFFSET+0x200) < 0) {
+            fprintf(stderr,"[ERR]  Seek to 0x%08"PRIx64" in sansa_update_of failed.\n",
+                       sansa->start+NVPARAMS_OFFSET+0x200);
+            return -1;
+        }
+        
+        memset(sansa->sectorbuf,0,NVPARAMS_SIZE);
+        n=sansa_write(sansa, NVPARAMS_SIZE);
+        if (n < NVPARAMS_SIZE) {
+            fprintf(stderr,"[ERR]  Short write in sansa_update_of\n");
+            return -1;
+        }
+    }
+    
+    return 0;
+}
+
+/* Update the PPBL (bootloader) image in the hidden firmware partition */
+int sansa_update_ppbl(struct sansa_t* sansa, const char* filename)
+{
+    int n;
+    int infile = -1;   /* Prevent an erroneous "may be used uninitialised" gcc warning */
+    int ppbl_length = 0; /* Keep gcc happy when building for rbutil */
+
+    /* Step 1 - read bootloader into RAM. */
+    infile=open(filename,O_RDONLY|O_BINARY);
+    if (infile < 0) {
+        fprintf(stderr,"[ERR]  Couldn't open input file %s\n",filename);
+        return -1;
+    }
+
+    ppbl_length = filesize(infile);
+
+    n = read(infile,sansa->sectorbuf+0x200,ppbl_length);
+    close(infile);
+    if (n < ppbl_length) {
+           fprintf(stderr,"[ERR]  Short read - requested %d bytes, received %d\n", ppbl_length, n);
+           return -1;
+    }
+
+    /* Step 2 - Build the header */
+    memset(sansa->sectorbuf,0,0x200);
+    memcpy(sansa->sectorbuf,"PPBL",4);
+    int2le(ppbl_length, sansa->sectorbuf+4);
+    int2le(0x00010000,  sansa->sectorbuf+8);
+
+    /* Step 3 - write the bootloader to the Sansa */
+    if (sansa_seek(sansa, sansa->start) < 0) {
+        fprintf(stderr,"[ERR]  Seek to 0x%08"PRIx64" in sansa_update_ppbl failed.\n", sansa->start);
+        return -1;
+    }
+
+    n=sansa_write(sansa, ppbl_length + 0x200);
+    if (n < (ppbl_length+0x200)) {
+        fprintf(stderr,"[ERR]  Short write in sansa_update_ppbl\n");
+        return -1;
+    }
+
+    return 0;
+}
+