The error:
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guix system: warning: The 'device' field of bootloader configurations is deprecated.
guix system: warning: Use 'target' instead.
substitute:
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...   0.0%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'... 100.0%
substitute:
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...   0.0%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'... 100.0%
substitute:
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...   0.0%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'... 100.0%
substitute:
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...   0.0%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'... 100.0%
substitute:
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...   0.0%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...  33.3%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...  66.7%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'... 100.0%
substitute:
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...   0.0%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...  33.3%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...  66.7%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'... 100.0%
substitute:
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...   0.0%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'... 100.0%
substitute:
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...   0.0%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'... 100.0%
substitute:
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'...   0.0%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'... 100.0%
Backtrace:
          14 (primitive-load "/gnu/store/xcnrc8lvq7yks3c02cpknphj3n0?")
In guix/ui.scm:
  1375:12 13 (run-guix-command _ . _)
In ice-9/boot-9.scm:
    837:9 12 (catch _ _ #<procedure b56555a8 at guix/ui.scm:451:2 (?> ?)
    837:9 11 (catch _ _ #<procedure b56555b8 at guix/ui.scm:539:6 (?> ?)
In guix/scripts/system.scm:
   1034:8 10 (_)
    909:6  9 (process-action _ _ _)
In guix/store.scm:
  1443:24  8 (run-with-store _ _ #:guile-for-build _ #:system _ # _)
In guix/scripts/system.scm:
   660:31  7 (_ _)
In srfi/srfi-1.scm:
   705:23  6 (filter-map #<procedure system->boot-parameters (sys?> . #)
In ice-9/boot-9.scm:
    837:9  5 (catch system-error #<procedure b9c3738 at guix/script?> ?)
In guix/scripts/system.scm:
   384:30  4 (_)
In gnu/system.scm:
   307:17  3 (read-boot-parameters-file "/var/guix/profiles/system-1?")
In ice-9/ports.scm:
   444:17  2 (call-with-input-file _ _ #:binary _ #:encoding _ # _)
In gnu/system.scm:
   282:10  1 (read-boot-parameters _)
    238:4  0 (device-sexp->device _)

gnu/system.scm:238:4: In procedure device-sexp->device:
gnu/system.scm:238:4: Throw to key `match-error' with args `("match" "no matching pattern" #f)'.


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the below is my config:


----------------
(use-modules (gnu) (gnu system nss))
(use-modules (gnu system locale))
(use-service-modules desktop)
(use-package-modules certs gnome)

(operating-system
 (host-name "tumashu")
 (timezone "Asia/Shanghai")
 (locale "zh_CN.UTF-8")
 (locale-definitions
  (cons* (locale-definition
          (name "zh_CN.GB2312")
          (source "zh_CN"))
         (locale-definition
          (name "zh_CN.GBK")
          (source "zh_CN"))
         (locale-definition
          (name "zh_CN.GB18030")
          (source "zh_CN"))
         (locale-definition
          (name "zh_TW.BIG5")
          (source "zh_TW"))
         (locale-definition
          (name "zh_TW.UTF-8")
          (source "zh_TW"))
         %default-locale-definitions))

 ;; Assuming /dev/sdX is the target hard disk
 (bootloader (grub-configuration (device "/dev/sda")))

 (file-systems
  (cons*
   (file-system
    (device "/dev/sda7")
    (title 'device)
    (mount-point "/")
    (type "ext4"))
   (file-system
    (device "/dev/sda5")
    (title 'device)
    (mount-point "/home")
    (type "ext4"))
   (file-system
    (device "/dev/sda6")
    (title 'device)
    (mount-point "/mnt/backup1")
    (type "ext4"))
   %base-file-systems))

 (swap-devices '("/dev/sda8"))

 (users (cons (user-account
               (name "feng")
               (comment "Feng Shu")
               (group "users")
               (supplementary-groups
                '("wheel" "netdev" "audio" "video"))
               (home-directory "/home/feng"))
              %base-user-accounts))

 ;; This is where we specify system-wide packages.
  (packages
   (append (map specification->package
                '("wpa-supplicant" 
                  "gvfs" "nss-certs"
                  "font-wqy-microhei"
                  ))
          %base-packages))

 ;; Add GNOME and/or Xfce---we can choose at the log-in
 ;; screen with F1.  Use the "desktop" services, which
 ;; include the X11 log-in service, networking with Wicd,
 ;; and more.
 (services (cons* (xfce-desktop-service)
                  %desktop-services))
 
 ;; Allow resolution of '.local' host names with mDNS.
 (name-service-switch %mdns-host-lookup-nss))




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