map (hd0,0)/boot/ghost.iso (0xff)map --hookchainloader (0xff)and still get the Error 5: Partition table invalid or corrupt error. I even pasted your values into the next line to do a side-by-side comparison and they were same as you had above. I extracted again from the iso and checked and still the same as the edited version.Using new grldr I get same Warning! Partition table og HD image is faulty(err=28) from chainloader I mentioned in previous post, but it still boots okay. FWIW it also works using (hd32) instead of (0xff). I have attached the first 512 bytes from one of the modified OSBOOT.IMG files in case I have done something wrong.