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When I boot my computer, whether it be from the OS software reboot button or the physical power button on my laptop, GRUB gives me a command line.

That, by itself, isn't so strange. I'd just assume I misconfigured something, except that if I type reboot into GRUB's command line, my computer reboots and GRUB gives me the normal boot menu as if nothing happened.

If I press c in the normal boot menu to get the command line again, and then type reboot into that, GRUB still returns to the normal menu after the reboot.

What could cause GRUB 2 to only initialize successfully when the reboot was instigated by its own command line?

I'm dual-booting Windows 7 and Arch Linux, both 64-bit. I'm using MBR, not UEFI. Here are the contents of /boot/grub/grub.cfg, which has been automatically generated by Arch's grub-mkconfig tool.

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
insmod part_gpt
insmod part_msdos
if [ -s $prefix/grubenv ]; then
  load_env
fi
if [ "${next_entry}" ] ; then
   set default="${next_entry}"
   set next_entry=
   save_env next_entry
   set boot_once=true
else
   set default="2"
fi

if [ x"${feature_menuentry_id}" = xy ]; then
  menuentry_id_option="--id"
else
  menuentry_id_option=""
fi

export menuentry_id_option

if [ "${prev_saved_entry}" ]; then
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
}

function load_video {
  if [ x$feature_all_video_module = xy ]; then
    insmod all_video
  else
    insmod efi_gop
    insmod efi_uga
    insmod ieee1275_fb
    insmod vbe
    insmod vga
    insmod video_bochs
    insmod video_cirrus
  fi
}

set menu_color_normal=white/red
set menu_color_highlight=red/white

if [ x$feature_default_font_path = xy ] ; then
   font=unicode
else
insmod part_msdos
insmod ext2
set root='hd0,msdos5'
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos5 --hint-efi=hd0,msdos5 --hint-baremetal=ahci0,msdos5  cdd2682e-3d7c-476f-bca9-9ce2d5be28f7
else
  search --no-floppy --fs-uuid --set=root cdd2682e-3d7c-476f-bca9-9ce2d5be28f7
fi
    font="/usr/share/grub/unicode.pf2"
fi

if loadfont $font ; then
  set gfxmode=auto
  load_video
  insmod gfxterm
  set locale_dir=$prefix/locale
  set lang=en_US
  insmod gettext
fi
terminal_input console
terminal_output gfxterm
set timeout=30
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/10_linux ###
menuentry 'Arch Linux, with Linux core repo kernel' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-core repo kernel-true-cdd2682e-3d7c-476f-bca9-9ce2d5be28f7' {
    load_video
    set gfxpayload=keep
    insmod gzio
    insmod part_msdos
    insmod ext2
    set root='hd0,msdos5'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos5 --hint-efi=hd0,msdos5 --hint-baremetal=ahci0,msdos5  cdd2682e-3d7c-476f-bca9-9ce2d5be28f7
    else
      search --no-floppy --fs-uuid --set=root cdd2682e-3d7c-476f-bca9-9ce2d5be28f7
    fi
    echo    'Loading Linux core repo kernel ...'
    linux   /boot/vmlinuz-linux root=UUID=cdd2682e-3d7c-476f-bca9-9ce2d5be28f7 ro  quiet
    echo    'Loading initial ramdisk ...'
    initrd  /boot/initramfs-linux.img
}
menuentry 'Arch Linux, with Linux core repo kernel (Fallback initramfs)' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-core repo kernel-fallback-cdd2682e-3d7c-476f-bca9-9ce2d5be28f7' {
    load_video
    set gfxpayload=keep
    insmod gzio
    insmod part_msdos
    insmod ext2
    set root='hd0,msdos5'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos5 --hint-efi=hd0,msdos5 --hint-baremetal=ahci0,msdos5  cdd2682e-3d7c-476f-bca9-9ce2d5be28f7
    else
      search --no-floppy --fs-uuid --set=root cdd2682e-3d7c-476f-bca9-9ce2d5be28f7
    fi
    echo    'Loading Linux core repo kernel ...'
    linux   /boot/vmlinuz-linux root=UUID=cdd2682e-3d7c-476f-bca9-9ce2d5be28f7 ro  quiet
    echo    'Loading initial ramdisk ...'
    initrd  /boot/initramfs-linux-fallback.img
}

### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/30_os-prober ###
menuentry 'Windows 7 (loader) (on /dev/sda2)' --class windows --class os $menuentry_id_option 'osprober-chain-CE7C7A0D7C79F097' {
    insmod part_msdos
    insmod ntfs
    set root='hd0,msdos2'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos2 --hint-efi=hd0,msdos2 --hint-baremetal=ahci0,msdos2  CE7C7A0D7C79F097
    else
      search --no-floppy --fs-uuid --set=root CE7C7A0D7C79F097
    fi
    chainloader +1
}
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f  ${config_directory}/custom.cfg ]; then
  source ${config_directory}/custom.cfg
elif [ -z "${config_directory}" -a -f  $prefix/custom.cfg ]; then
  source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###

### BEGIN /etc/grub.d/60_memtest86+ ###
### END /etc/grub.d/60_memtest86+ ###
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up vote 2 down vote accepted

I remember similar issues, on different occasions, and I started noticing it was happening anytime there were kernel upgrades or grub upgrades (I believe so anyway, re-install always fixed it).

Have Arch regenerate grub.cfg at minimum, although it kinda sounds like initrd/initramfs and grub went out of sync. There is another boot resource that might not hurt to check, but I can't thing of it.

Anyway, if you made any updates/installs, go check your syslogs and find out what they were, and undo them one at a time, or just roll them all back.

Maybe your BIOS is also going schizophrenic on you, but its much more likely that package updates were not gracefully synchronized.

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