flash/extract/extract.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2003 by Jörg Hohensohn
  11  *
  12  * Tool to extract the scrambled image out of an Archos flash ROM dump
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  * KIND, either express or implied.
  21  *
  22  ****************************************************************************/
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <memory.h>
  27
  28 #define UINT8 unsigned char
  29 #define UINT16 unsigned short
  30 #define UINT32 unsigned long
  31
  32 #define IMAGE_HEADER 0x6000 // a 32 byte header in front of the software image
  33 #define IMAGE_START  0x6020     // software image position in Flash
  34
  35
  36 // place a 32 bit value into memory, big endian
  37 void Write32(UINT8* pByte, UINT32 value)
  38 {
  39         pByte[0] = (UINT8)(value >> 24);
  40         pByte[1] = (UINT8)(value >> 16);
  41         pByte[2] = (UINT8)(value >> 8);
  42         pByte[3] = (UINT8)(value);
  43 }
  44
  45
  46 // read a 32 bit value from memory, big endian
  47 UINT32 Read32(UINT8* pByte)
  48 {
  49         UINT32 value = 0;
  50
  51         value |= (UINT32)pByte[0] << 24;
  52         value |= (UINT32)pByte[1] << 16;
  53         value |= (UINT32)pByte[2] << 8;
  54         value |= (UINT32)pByte[3];
  55
  56         return value;
  57 }
  58
  59
  60 // entry point
  61 int main(int argc, char* argv[])
  62 {
  63         FILE* pInFile;
  64         FILE* pOutFile;
  65         UINT8 aHeader[6];
  66         UINT8 aImage[256*1024];
  67         UINT32 i;
  68         UINT32 uiSize, uiStart;
  69         UINT16 usChecksum = 0;
  70
  71         if (argc < 2)
  72         {
  73                 printf("Extract the software image out of an original Archos Flash ROM dump.\n");
  74                 printf("Result is a scrambled file, use the descramble tool to get the binary,\n");
  75                 printf(" always without the -fm option, even if processing an FM software.\n\n");
  76                 printf("Usage: extract <flash dump file> <output file>\n");
  77                 printf("Example: extract internal_rom_2000000-203FFFF.bin archos.ajz\n");
  78                 exit(0);
  79         }
  80
  81         pInFile = fopen(argv[1], "rb");
  82         if (pInFile == NULL)
  83         {
  84                 printf("Error opening input file %s\n", argv[1]);
  85                 exit(1);
  86         }
  87
  88         if (fread(aImage, 1, sizeof(aImage), pInFile) != sizeof(aImage))
  89         {
  90                 printf("Error reading input file %s, must be 256kB in size.\n", argv[1]);
  91                 fclose(pInFile);
  92                 exit(2);
  93         }
  94         fclose(pInFile);
  95
  96         // find out about the type
  97         uiStart = Read32(aImage + 8);
  98         uiSize = Read32(aImage + 12); // booted ROM image
  99         if (uiStart == 0x02000100 && uiSize > 20000)
 100         {       // Player has no loader, starts directly with the image
 101                 uiStart = 0x0100;
 102         }
 103         else
 104         {       // Recorder / FM / V2 Recorder
 105                 uiStart = IMAGE_START;
 106                 uiSize = Read32(aImage + IMAGE_HEADER + 4); // size record of header
 107         }
 108
 109         // sanity check
 110         if (uiSize > sizeof(aImage) - uiStart || uiSize < 40000)
 111         {
 112                 printf("Error: Impossible image size &d bytes.\n", uiSize);
 113                 exit(3);
 114         }
 115
 116         // generate checksum
 117         for (i=0; i<uiSize; i++)
 118         {
 119                 UINT8 byte;
 120                 byte = aImage[uiStart + i];
 121                 byte = ~((byte >> 1) | ((byte << 7) & 0x80)); /* poor man's ROR */
 122                 usChecksum += byte;
 123         }
 124
 125         // make header
 126         Write32(aHeader + 2, usChecksum); // checksum in 5th and 6th byte
 127         Write32(aHeader, uiSize); // size in first 4 bytes
 128
 129         pOutFile = fopen(argv[2], "wb");
 130         if (pOutFile == NULL)
 131         {
 132                 printf("Error opening output file %s\n", argv[2]);
 133                 exit(4);
 134         }
 135
 136         if (fwrite(aHeader, 1, sizeof(aHeader), pOutFile) != sizeof(aHeader)
 137          || fwrite(aImage + uiStart, 1, uiSize, pOutFile) != uiSize)
 138         {
 139                 printf("Write error\n");
 140                 fclose(pOutFile);
 141                 exit(5);
 142         }
 143
 144         fclose(pOutFile);
 145
 146         return 0;
 147 }