Package: wimtools Version: 1.11.0-1 mkwinpeimg --iso tries to invoke mkisofs, which is not provided by any package.
As per the wiki[0], the package mkisofs is no longer available in debian and the preferred replacement is xorriso. Both xorriso and genisoimage have command-line compatibility with mkisofs, so a workaround is to create a symlink: ln -s /usr/bin/xorriso /usr/bin/mkisofs Here's the output before creating the symlink: $ mkwinpeimg --iso --windows-dir="$dir" winpe.iso ERROR: To make a bootable ISO image of Windows PE, we need the "mkisofs" program, but it doesn't seem to be installed. Please install the "cdrkit" package to continue, or try omitting the --iso option to make a disk image instead of an ISO image. Here's the output afterwards: $ ln -s /usr/bin/xorriso /usr/bin/mkisofs $ mkwinpeimg --iso --windows-dir="dir/" winpe.iso :: Copying primary boot files from mounted Windows ISO (dir/) [DONE] :: Exporting image from "dir//sources/boot.wim" [BUSY] Using LZX compression with 1 thread Archiving file data: 641 MiB of 641 MiB (100%) done [DONE] :: Making ISO image "winpe.iso" [BUSY] xorriso 1.4.6 : RockRidge filesystem manipulator, libburnia project. [DONE] The image (winpe.iso) is 257501184 bytes. This happens in Debian Stretch: $ apt-cache policy wimtools wimtools: Instalados: 1.11.0-1 Candidato: 1.11.0-1 Tabla de versión: *** 1.11.0-1 500 500 http://ftp.us.debian.org/debian stretch/main i386 Packages 100 /var/lib/dpkg/status $ apt-cache policy xorriso xorriso: Instalados: 1.4.6-1+b1 Candidato: 1.4.6-1+b1 Tabla de versión: *** 1.4.6-1+b1 500 500 http://ftp.us.debian.org/debian stretch/main i386 Packages 100 /var/lib/dpkg/status $ apt-cache policy genisoimage genisoimage: Instalados: 9:1.1.11-3+b2 Candidato: 9:1.1.11-3+b2 Tabla de versión: *** 9:1.1.11-3+b2 500 500 http://ftp.us.debian.org/debian stretch/main i386 Packages 100 /var/lib/dpkg/status [0]: https://wiki.debian.org/genisoimage