External USB hard disk fails to boot

Question

I installed Arch Linux on an external USB Lacie 1 TB Hard Disk. I followed instructions on WiKi: "install from exisiting linux", method 2, since I already have Linux installed
on the internal HDD of my laptop (dual boot with Windows, also with Grub as bootloader).
Problem: The external HDD stalls during boot right after the "Welcome to Grub!" - message. I can only hard-reset my laptop from there.
The external HDD has msdos Partition Table.  It is recognized by BIOS just fine, since I can choose to boot from it. It has following (very simple) partition setup:
[root@arch-laptop chris]# fdisk -l /dev/sdb
Disk /dev/sdb: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x000c9610
Device Boot Start End Blocks Id System
/dev/sdb1 * 2048 40962047 20480000 83 Linux
So there's just the root partition, no boot or home partition defined. Grub installed to the external HDD with no errors.
Here's the grub.cfg auto-generated, without anything adapted.  The UUID of the external HDD /dev/sdb1 is correct.
[root@arch-laptop grub]# cat grub.cfg
# 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="${next_entry}"
set next_entry=
save_env next_entry
set boot_once=true
else
set default="0"
fi
if [ x"${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$feature_all_video_module = xy ]; then
insmod all_video
else
insmod efi_gop
insmod efi_uga
insmod ieee1275_fb
insmod vbe
insmod vga
insmod video_bochs
insmod video_cirrus
fi
if [ x$feature_default_font_path = xy ] ; then
font=unicode
else
insmod part_msdos
insmod ext2
set root='hd1,msdos1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd1,msdos1 --hint-efi=hd1,msdos1 --hint-baremetal=ahci1,msdos1 5fe1d28c-2640-4b5c-b98b-75d147479348
else
search --no-floppy --fs-uuid --set=root 5fe1d28c-2640-4b5c-b98b-75d147479348
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
if [ x$feature_timeout_style = xy ] ; then
set timeout_style=menu
set timeout=5
# Fallback normal timeout code in case the timeout_style feature is
# unavailable.
else
set timeout=5
fi
### END /etc/grub.d/00_header ###
### BEGIN /etc/grub.d/10_archlinux ###
menuentry "Arch Linux pkg-linux kernel" --class arch-linux --class arch --class gnu-linux --class gnu --class os {
if [ x$feature_all_video_module = xy ]; then
insmod all_video
fi
set gfxpayload=keep
insmod ext2
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd1,msdos1 --hint-efi=hd1,msdos1 --hint-baremetal=ahci1,msdos1 5fe1d28c-2640-4b5c-b98b-75d147479348
else
search --no-floppy --fs-uuid --set=root 5fe1d28c-2640-4b5c-b98b-75d147479348
fi
echo 'Loading Arch Linux pkg-linux kernel ...'
linux /boot/vmlinuz-linux root=UUID=5fe1d28c-2640-4b5c-b98b-75d147479348 rw quiet
echo 'Loading Arch Linux pkg-linux kernel initramfs ...'
initrd /boot/initramfs-linux.img
menuentry "Arch Linux pkg-linux kernel (fallback initramfs)" --class arch-linux --class arch --class gnu-linux --class gnu --class os {
if [ x$feature_all_video_module = xy ]; then
insmod all_video
fi
set gfxpayload=keep
insmod ext2
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd1,msdos1 --hint-efi=hd1,msdos1 --hint-baremetal=ahci1,msdos1 5fe1d28c-2640-4b5c-b98b-75d147479348
else
search --no-floppy --fs-uuid --set=root 5fe1d28c-2640-4b5c-b98b-75d147479348
fi
echo 'Loading Arch Linux pkg-linux kernel ...'
linux /boot/vmlinuz-linux root=UUID=5fe1d28c-2640-4b5c-b98b-75d147479348 rw quiet
echo 'Loading Arch Linux pkg-linux kernel fallback initramfs ...'
initrd /boot/initramfs-linux-fallback.img
### END /etc/grub.d/10_archlinux ###
### BEGIN /etc/grub.d/10_linux ###
menuentry 'Arch Linux' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-5fe1d28c-2640-4b5c-b98b-75d147479348' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_msdos
insmod ext2
set root='hd1,msdos1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd1,msdos1 --hint-efi=hd1,msdos1 --hint-baremetal=ahci1,msdos1 5fe1d28c-2640-4b5c-b98b-75d147479348
else
search --no-floppy --fs-uuid --set=root 5fe1d28c-2640-4b5c-b98b-75d147479348
fi
echo 'Loading Linux linux ...'
linux /boot/vmlinuz-linux root=UUID=5fe1d28c-2640-4b5c-b98b-75d147479348 rw quiet
echo 'Loading initial ramdisk ...'
initrd /boot/initramfs-linux.img
submenu 'Advanced options for Arch Linux' $menuentry_id_option 'gnulinux-advanced-5fe1d28c-2640-4b5c-b98b-75d147479348' {
menuentry 'Arch Linux, with Linux linux' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-linux-advanced-5fe1d28c-2640-4b5c-b98b-75d147479348' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_msdos
insmod ext2
set root='hd1,msdos1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd1,msdos1 --hint-efi=hd1,msdos1 --hint-baremetal=ahci1,msdos1 5fe1d28c-2640-4b5c-b98b-75d147479348
else
search --no-floppy --fs-uuid --set=root 5fe1d28c-2640-4b5c-b98b-75d147479348
fi
echo 'Loading Linux linux ...'
linux /boot/vmlinuz-linux root=UUID=5fe1d28c-2640-4b5c-b98b-75d147479348 rw quiet
echo 'Loading initial ramdisk ...'
initrd /boot/initramfs-linux.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 ###
### 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+ ###
the internal HDD (/dev/sda) also has GRUB installed, without any problems, with a graphical console menu.
GRUB version is 2.02
laptop: dv6-6b41ed
Legacy BIOS  (no EFI / UEFI).
Any ideas on how to solve / troubleshoot this?
Last edited by christopher72 (2014-04-21 15:05:21)

Answer 1

Any hooks in particular? I don't know which hook to add other then the 'blocks' hook, which is there already:
HOOKS="base udev autodetect modconf block filesystems keyboard fsck"
Also, I don't think that could be the problem since loading the initramfs image takes place after choosing something from the Grub Menu.  That menu never appears, I just get "welcome to grub!" with a blinking cursor underneath.
I did add "insmod usbms" in grub.cfg,  but that didn't change anything.
What strikes me as odd is that in grub.cfg, the disk is referred to as "hd1", where I think it could just as well be "hd0" if that's the first hard disk the BIOS boots from. But I'm not sure if that really matters since the search is done with the UUID.
Another thing I tested earlier:  I dd 'd the Arch Live image to the external usb HDD, and then it boots fine...