Alexandre:
When the PE file is generate in EXE have just the "M" of "MZ"...
Let's try again, is this better? import std.c.windows.windows: WORD, LONG; struct IMAGE_DOS_HEADER { WORD e_magic = ('M' << 8) + 'Z', e_cblp, e_cp, e_crlc, e_cparhdr, e_minalloc, e_maxalloc, e_ss, e_sp, e_csum, e_ip, e_cs, e_lfarlc, e_ovno; WORD[4] e_res; WORD e_oemid, e_oeminfo; WORD[10] e_res2; LONG e_lfanew; } alias PIMAGE_DOS_HEADER = IMAGE_DOS_HEADER*; __gshared ubyte[0x800] image; void main() { import std.stdio; import core.stdc.string; auto dosh = cast(PIMAGE_DOS_HEADER)image.ptr; immutable stub = x"b8 01 4c cd 21"; memcpy(&image[IMAGE_DOS_HEADER.sizeof], stub.ptr, stub.length); } Bye, bearophile