boot the Hurd with Guix

[rennes]

Hello Hurd,

I'm trying boot GNU hurd with guix binaries generated with cross compilation. 
During start-up progresses and stops in root filesystem, how I can debug to see 
the error ?

/-------------------------Qemu output-------------------------------/
          Loading GNU Mach ..
          Loading the Hurd ..
          ..
          .
 module 0: ext2fs --multiboot-command-line=${kernel-command-line} 
--host-priv-por
          t=${host-port} --device-master-port=${device-port} 
--exec-server-task=${exec-tas
          k} -T typed ${root} $(task-create) $(task-resume)
          module 1: exec /hurd/exec $(exec-task=task-create)
          2 multiboot modules
          task loaded: ext2fs --multiboot-command-line=root=device:hd0s1 -s 
--host-priv-po
          rt=1 --device-master-port=2 --exec-server-task=3 -T typed device:hd0s1
          task loaded: exec /hurd/exec

          start ext2fs: 
/--------------------------------------------------------/

This is the content of the grub.cfg file:

/--------------------------------------------------------/
insmod part_msdos
insmod ext2
set root='hd0,msdos1'
set menu_color_normal=cyan/blue
set menu_color_highlight=white/black
set timeout=2

menuentry 'GNU Guix/Hurd' {
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos1'
        echo 'Loading GNU Mach ..'
        multiboot /boot/gnumach.gz root=device:hd0s1 -s
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos1'
        echo 'Loading the Hurd ..'
        module /hurd/ext2fs.static ext2fs \
                --multiboot-command-line='${kernel-command-line}' \
                --host-priv-port='${host-port}' \
                --device-master-port='${device-port}' \
                --exec-server-task='${exec-task}' -T typed '${root}' \
                '$(task-create)' '$(task-resume)'
        module 
/gnu/store/f70f5z47i2i8fpx716fw59laijjs2jb7-glibc-cross-i586-pc-gnu-2.23/lib/ld.so.1
 exec /tools/hurd/exec '$(exec-task=task-create)'

/--------------------------------------------------------/