Last active
July 29, 2020 14:04
-
-
Save flyinprogrammer/8de3b6e795ae2d7e8ed7a8ea15e5eded to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#include <stdio.h> | |
#include <stdint.h> | |
typedef uint32_t DWORD; | |
typedef uint16_t WORD; | |
int main(int argc, char *argv[]) { | |
char *filename = "firmware.bin"; | |
FILE *input_file; | |
if (argc > 1) | |
filename = argv[1]; | |
fprintf(stderr, "Opening file %s\n", filename); | |
input_file = fopen(filename, "r"); | |
DWORD dLength, dCheckSum, dExpectedCheckSum, dAddress, i, dImageBuf[512*1024]; | |
WORD wSignature; | |
fread(&wSignature,1,2,input_file); // read signature bytes | |
if (wSignature != 0x5943) // check ‘CY’ signature byte | |
{ | |
printf("Invalid image"); | |
return 1; | |
} | |
fread(&i, 2, 1, input_file); // skip 2 dummy bytes | |
dCheckSum = 0; | |
while (1) | |
{ | |
fread(&dLength,4,1,input_file); // read dLength | |
fread(&dAddress,4,1,input_file); // read dAddress | |
if (dLength==0) break; // done | |
// read sections | |
fread(dImageBuf, 4, dLength, input_file); | |
for (i=0; i<dLength; i++) dCheckSum += dImageBuf[i]; | |
} | |
printf("checksum: %#x\n", dCheckSum); | |
// read pre-computed checksum data | |
fread(&dExpectedCheckSum, 4, 1, input_file); | |
printf("expected checksum: %#x\n", dExpectedCheckSum); | |
if (dCheckSum != dExpectedCheckSum) | |
{ | |
printf("Fail to boot due to checksum error (calculated %#x != file %#x)\n", dCheckSum, dExpectedCheckSum); | |
return 1; | |
} | |
return 0; | |
} |
#include <stdio.h>
#include <stdint.h>
int main(int argc, char **argv) {
unsigned long ulong;
unsigned short ushort;
uint32_t uint32Magic;
uint16_t uInt16Magic;
printf("the size of unsigned long %ld\n", sizeof(ulong) );
printf("the size of unsigned short %ld\n", sizeof(ushort) );
printf("the size of uint32_t %ld\n", sizeof(uint32Magic) );
printf("the size of uint16_t %ld\n", sizeof(uInt16Magic) );
return 0;
}
yields:
the size of unsigned long 8
the size of unsigned short 2
the size of uint32_t 4
the size of uint16_t 2
Lols, so don't I feel silly now. Thanks for your help @miek!
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
I think the problem is that
dCheckSum
is too wide, it should only be 32-bits. Here's the version I used for reference: https://gist.github.com/miek/b6248205b6cfd26c1c6c5d6ac0abdc3d