(define-module (gnu system serinstall)
  #:use-module (gnu system)
  #:use-module (gnu system install)
  #:use-module (gnu services base)
  #:use-module (gnu bootloader)
  #:use-module (gnu bootloader grub)
  #:use-module (nongnu system install)
  #:use-module (guix gexp)
  #:export (installation-os-serial))

(define installation-os-serial
  (operating-system
    (inherit installation-os)
    (bootloader (bootloader-configuration
		 (bootloader grub-bootloader)
		 (terminal-outputs 'serial_0)
		 (terminal-inputs 'serial_0)
		 (serial-unit 0)
		 (serial-speed 115200)))
    (kernel-arguments '("console=ttyS0,115200n8"))
    (services
     (cons
      (agetty-service (agetty-configuration
		       (extra-options '("-L"))
		       (term "vt100")
		       (tty "ttyS0")
		       (baud-rate "115200")
		       (auto-login "root")
		       (login-pause? #t)))
      %installation-services))))

installation-os-serial

# guix system disk-image /home/apfel/custom-install-disk.scm
/home/apfel/custom-install-disk.scm:23:6: error: %installation-services: unbound variable
hint: Did you forget `(use-modules (gnu system install))'?

> this error make sense, %installation-services are not exported. But how can i do this then?
> i use the guix package manager on a gentoo box to create this image.