This is a "script" I wrote to decompress bFLTv4 binaries. I wrote it a few weeks ago when I was messing around with and attempting to disassemble firmware from IoT cameras.
#include <stdlib.h>
#include <stdio.h>
#define BFLT_HEADER_SIZE 0x40
int main(int argc, char **argv) {
FILE *bflt_file = fopen(argv[1], "rb");
FILE *tmp_file = fopen("/tmp/bflt_content.gz", "wb");
FILE *new_file = fopen(argv[2], "wb");
if(bflt_file == NULL) {
printf("Error opening file or file does not exist.");
return 1;
}
fseek(bflt_file, 0L, SEEK_END);
unsigned long file_size = ftell(bflt_file);
fseek(bflt_file, 0L, SEEK_SET);
char *bflt_header = malloc(sizeof(char) * BFLT_HEADER_SIZE);
char *bflt_content = malloc(sizeof(char) * file_size);
fread(bflt_header, 1, BFLT_HEADER_SIZE, bflt_file);
bflt_header[0x27] = bflt_header[0x27] & 3; //Change header flag from compressed to uncompressed
fseek(bflt_file, 0x40L, SEEK_SET);
fread(bflt_content, 1, file_size-0x40, bflt_file);
fwrite(bflt_content, 1, file_size-0x40, tmp_file);
fclose(tmp_file);
system("gzip -d /tmp/bflt_content.gz");
FILE *raw_file = fopen("/tmp/bflt_content", "rb");
fseek(raw_file, 0L, SEEK_END);
unsigned long raw_file_size = ftell(raw_file);
fseek(raw_file, 0L, SEEK_SET);
char *raw_content = malloc(sizeof(char) * raw_file_size);
fread(raw_content, 1, raw_file_size, raw_file);
fwrite(bflt_header, 1, 0x40, new_file);
fseek(new_file, 0x40L, SEEK_SET);
fwrite(raw_content, 1, raw_file_size, new_file);
fclose(new_file);
fclose(bflt_file);
fclose(raw_file);
free(raw_content);
free(bflt_header);
free(bflt_content);
return 0;
}
