Mistake: Using dd with a bs=512 but forgetting to skip the first sector.
Result: The repacked file is 512 bytes too large; the bootloader reads garbage.
Solution: Always align to 0x1000 (4096 bytes). Use bs=4k if possible.
import struct, zlib, os
def repack_ewptx(input_dir, file_list, output_file, flags=0): entries = [] data_offset = 32 + len(file_list)*48 # header + table size with open(output_file, 'wb') as out: # placeholder header out.write(b'EWPT' + struct.pack('<IIII', 1, len(file_list), 32, flags)) # write placeholder table out.write(b'\x00' * (len(file_list)*48)) # write data for idx, fname in enumerate(file_list): with open(os.path.join(input_dir, fname), 'rb') as fin: orig_data = fin.read() comp_data = zlib.compress(orig_data) # adjust compression # encryption here if needed offset = out.tell() out.write(comp_data) entries.append((idx, offset, len(comp_data), len(orig_data))) # go back and write table out.seek(32) for idx, (_, off, csize, dsize) in enumerate(entries): entry = struct.pack('<QIIIIBB', idx, off, csize, dsize, 0, 1, 0) + b'\x00'*18 out.write(entry)ewptx dump repack
Real-world repacking often fails due to hardcoded offsets or integrity checks (signatures, checksums elsewhere). You may need to patch the main executable. Mistake: Using dd with a bs=512 but forgetting
Most EWPTX dumps are partially encrypted with AES-XTS. Real-world repacking often fails due to hardcoded offsets