reorganise a windows boot disk

I had downloaded a bad windows ISO container - it would not boot under VirtualBox.

But with some Ubuntu tricks - I recreated a new ISO and got Windows 7 up and running.

Ubuntu Mount the drive

I booted into Ubuntu (It as a VM running on the mac) and with the Mac drive mounted as a shared_folder did

sudo mount -o loop /dir/bad.iso /cdrom

1 ISO all mounted...

mkisofs

This is a command with more options than I think I have ever seen before.

but with some Googleness .... I found

mkisofs -udf -v -b BOOT/ETFSBOOT.COM -no-emul-boot -hide boot.bin -hide boot.catalog -o /media/sf_Mac/new.iso .

Back to VirtualBox

Create machine -> Select new.iso -> boot

Easy peasy