Untested (i.e. will almost certainly brick your device if you attempt to use it) first attempt at making mkamsboot store the original firmware as a UCL compressed image. If it works, then this means we have about 40KB (depending on target and OF version) for our bootloader code. I repeat: This is UNTESTED and needs reviewing fully before attempting to install on a device.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@18675 a1c6a512-1295-4272-9138-f99709370657

utils/AMS/hacking/extract_fw.c

@@ -0,0 +1,129 @@
+/*
+
+extract_fw.c - extract the main firmware image from a Sansa V2 (AMS) firmware
+               file
+
+Copyright (C) Dave Chapman 2008
+
+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 program 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110, USA
+
+*/
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+
+
+/* Win32 compatibility */
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
+
+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);
+    }
+}
+
+static uint32_t get_uint32le(unsigned char* p)
+{
+    return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
+}
+
+void usage(void)
+{
+    printf("Usage: extract_fw <firmware file> <output file>\n");
+
+    exit(1);
+}
+
+int main(int argc, char* argv[])
+{
+    char *infile, *outfile;
+    int fdin, fdout;
+    off_t len;
+    uint32_t n;
+    unsigned char* buf;
+    uint32_t firmware_size;
+
+    if(argc != 3) {
+        usage();
+    }
+
+    infile = argv[1];
+    outfile = argv[2];
+
+    /* Open the firmware file */
+    fdin = open(infile,O_RDONLY|O_BINARY);
+
+    if (fdin < 0) {
+        fprintf(stderr,"[ERR]  Could not open %s for reading\n",infile);
+        return 1;
+    }
+
+    if ((len = filesize(fdin)) < 0)
+        return 1;
+
+    /* We will need no more memory than the total size plus the bootloader size
+       padded to a boundary */
+    if ((buf = malloc(len)) == NULL) {
+        fprintf(stderr,"[ERR]  Could not allocate buffer for input file (%d bytes)\n",(int)len);
+        return 1;
+    }
+
+    n = read(fdin, buf, len);
+
+    if (n != (uint32_t)len) {
+        fprintf(stderr,"[ERR] Could not read firmware file\n");
+        return 1;
+    }
+
+    close(fdin);
+
+    /* Get the firmware size */
+    firmware_size = get_uint32le(&buf[0x0c]);
+
+    fdout = open(outfile, O_CREAT|O_TRUNC|O_WRONLY|O_BINARY,0666);
+
+    if (fdout < 0) {
+        fprintf(stderr,"[ERR]  Could not open %s for writing\n",outfile);
+        return 1;
+    }
+
+    n = write(fdout, buf + 0x400, firmware_size);
+
+    if (n != (uint32_t)firmware_size) {
+        fprintf(stderr,"[ERR] Could not write firmware block\n");
+        return 1;
+    }
+
+    /* Clean up */
+    close(fdout);
+    free(buf);
+
+    return 0;
+}