On 2020-12-27 at 16:36, Anssi Saari wrote: > The Wanderer <wanderer@fastmail.fm> writes: > >> I need to get that live-boot medium ready and do those tests. > > That seems like a good thing to do. I have it ready now, but haven't shut down for another swap, in part because I've been napping. I may do it tonight, or more likely, tomorrow. > Another thing you could do is post your grub.cfg. It seems a little > odd you haven't. It mainly just hadn't occurred to me, in part (though only in part) because I thought I recalled that the boot-configuration files for GRUB2 weren't the same as from legacy GRUB (and might even be stored in multiple files) and had a mental association of that file with legacy GRUB, so didn't trust it to necessarily be the correct / full config. Now that it's been suggested, I have a bit of concern about posting a file containing filesystem (and other related?) UUIDs; that's probably excessive paranoia (last time I needed to post a file containing complex IDs like that some of them were encryption-key hashes), but I've still chosen to sed them out into generic form before attaching the result. That's the only difference between the attachment and the original. I don't expect there to be any useful / relevant information there, but one never knows. It occurs to me that it might be worthwhile to note down some get-information commands from the GRUB documentation, and stop at the GRUB menu next time I'm booting with the old / current GPU to see whether I can extract anything that might be helpful. > Also from previous discussion I think it's worth mentioning that Grub > doesn't actually read /etc/default/grub, update-grub reads it to > generate /boot/grub/grub.cfg. So only editing /etc/default/grub > doesn't change Grub config in any way. Yes, I know that much. After applying the change, I ran update-grub to re-generate the config files appropriately. > If you're up for it, you could setup a serial terminal and send Grub > output to serial and/or console. That way you might be able to boot > and wouldn't have to switch video cards to try different > configurations. But if you only have that one computer then I guess > not. We have at least a dozen computers in the household, if you count servers and laptops, and AFAIK a plurality of them are Debian-based. What we don't have is A: any experience with working with serial console, or B: (that I know of) any cables that might work to connect two computers that way. I have the impression that things have by now developed to the point where a physical serial-port cable (of the classic type of serial port and cable, whose connectors can be visually confused with a VGA port in some cases) is no longer necessary, which is good, since if we ever had such a thing it was at least back in the days of PS/2 keyboards and mice and might have been back in the days before our home computers had internal hard drives. I imagine USB would be the replacement (just based on the name), and I'm also aware of the existence (kernel-side) of netconsole, but how to use either for this I don't know. -- The Wanderer The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man. -- George Bernard Shaw
#
# 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 ###
if [ -s $prefix/grubenv ]; then
set have_grubenv=true
load_env
fi
if [ "${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$feature_all_video_module = xy ]; then
insmod all_video
else
insmod efi_gop
insmod efi_uga
insmod ieee1275_fb
insmod vbe
insmod vga
insmod video_bochs
insmod video_cirrus
fi
}
terminal_input console
terminal_output console
if [ "${recordfail}" = 1 ] ; then
set timeout=30
else
if [ x$feature_timeout_style = xy ] ; then
set timeout_style=menu
set timeout=5
# Fallback normal timeout code in case the timeout_style feature is
# unavailable.
else
set timeout=5
fi
fi
### END /etc/grub.d/00_header ###
### BEGIN /etc/grub.d/05_debian_theme ###
set menu_color_normal=cyan/blue
set menu_color_highlight=white/blue
### END /etc/grub.d/05_debian_theme ###
### BEGIN /etc/grub.d/10_linux ###
function gfxmode {
set gfxpayload="${1}"
}
set linux_gfx_mode=
export linux_gfx_mode
menuentry 'Debian GNU/Linux' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-UUID_1' {
load_video
insmod gzio
if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
insmod part_msdos
insmod part_msdos
insmod diskfilter
insmod mdraid1x
insmod lvm
insmod ext2
set root='lvmid/LVM_UUID'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint='lvmid/LVM_UUID' UUID_2
else
search --no-floppy --fs-uuid --set=root UUID_2
fi
echo 'Loading Linux 5.9.0-5-amd64 ...'
linux /vmlinuz-5.9.0-5-amd64 root=/dev/mapper/vg_system-lv_root ro intremap=off acpi_enforce_resources=lax
echo 'Loading initial ramdisk ...'
initrd /initrd.img-5.9.0-5-amd64
}
submenu 'Advanced options for Debian GNU/Linux' $menuentry_id_option 'gnulinux-advanced-UUID_1' {
menuentry 'Debian GNU/Linux, with Linux 5.9.0-5-amd64' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.9.0-5-amd64-advanced-UUID_1' {
load_video
insmod gzio
if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
insmod part_msdos
insmod part_msdos
insmod diskfilter
insmod mdraid1x
insmod lvm
insmod ext2
set root='lvmid/LVM_UUID'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint='lvmid/LVM_UUID' UUID_2
else
search --no-floppy --fs-uuid --set=root UUID_2
fi
echo 'Loading Linux 5.9.0-5-amd64 ...'
linux /vmlinuz-5.9.0-5-amd64 root=/dev/mapper/vg_system-lv_root ro intremap=off acpi_enforce_resources=lax
echo 'Loading initial ramdisk ...'
initrd /initrd.img-5.9.0-5-amd64
}
menuentry 'Debian GNU/Linux, with Linux 5.9.0-5-amd64 (recovery mode)' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.9.0-5-amd64-recovery-UUID_1' {
load_video
insmod gzio
if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
insmod part_msdos
insmod part_msdos
insmod diskfilter
insmod mdraid1x
insmod lvm
insmod ext2
set root='lvmid/LVM_UUID'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint='lvmid/LVM_UUID' UUID_2
else
search --no-floppy --fs-uuid --set=root UUID_2
fi
echo 'Loading Linux 5.9.0-5-amd64 ...'
linux /vmlinuz-5.9.0-5-amd64 root=/dev/mapper/vg_system-lv_root ro single intremap=off
echo 'Loading initial ramdisk ...'
initrd /initrd.img-5.9.0-5-amd64
}
menuentry 'Debian GNU/Linux, with Linux 5.9.0-4-amd64' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.9.0-4-amd64-advanced-UUID_1' {
load_video
insmod gzio
if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
insmod part_msdos
insmod part_msdos
insmod diskfilter
insmod mdraid1x
insmod lvm
insmod ext2
set root='lvmid/LVM_UUID'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint='lvmid/LVM_UUID' UUID_2
else
search --no-floppy --fs-uuid --set=root UUID_2
fi
echo 'Loading Linux 5.9.0-4-amd64 ...'
linux /vmlinuz-5.9.0-4-amd64 root=/dev/mapper/vg_system-lv_root ro intremap=off acpi_enforce_resources=lax
echo 'Loading initial ramdisk ...'
initrd /initrd.img-5.9.0-4-amd64
}
menuentry 'Debian GNU/Linux, with Linux 5.9.0-4-amd64 (recovery mode)' --class debian --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.9.0-4-amd64-recovery-UUID_1' {
load_video
insmod gzio
if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
insmod part_msdos
insmod part_msdos
insmod diskfilter
insmod mdraid1x
insmod lvm
insmod ext2
set root='lvmid/LVM_UUID'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint='lvmid/LVM_UUID' UUID_2
else
search --no-floppy --fs-uuid --set=root UUID_2
fi
echo 'Loading Linux 5.9.0-4-amd64 ...'
linux /vmlinuz-5.9.0-4-amd64 root=/dev/mapper/vg_system-lv_root ro single intremap=off
echo 'Loading initial ramdisk ...'
initrd /initrd.img-5.9.0-4-amd64
}
}
### 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/30_uefi-firmware ###
### END /etc/grub.d/30_uefi-firmware ###
### 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 ###
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