Grub/Ubuntu: Couldn't find suitable memory target after kernel upgrade

Question

Shortly after the new kernel versions were released for the Spectre and Meltdown issues (perhaps unrelated) I installed the latest kernel update, which at the time was 4.13.0-25.29. As soon as I rebooted I received the Grub error "Couldn't find suitable memory target".

I found that using the previous kernel fixed the problem. So far here is the list of working and broken kernels.

4.13.0-21.24 works
4.13.0-25.29 errors
4.13.0-31.34 errors
4.13.0-32.35 errors

Any ideas of how I can fix this to use the newer kernels without needing to reinstall the OS?

/etc/default/grub:

GRUB_DEFAULT=0
GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

/boot/grub/grub.cfg:

# Broken entry (disk UUID has been replaced)
menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-[DISK-UUID]' {
    recordfail
    load_video
    gfxmode $linux_gfx_mode
    insmod gzio
    if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
    insmod part_gpt
    insmod ext2
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root  [DISK-UUID]
    else
      search --no-floppy --fs-uuid --set=root [DISK-UUID]
    fi
    linux   /boot/vmlinuz-4.13.0-32-generic.efi.signed root=UUID=[DISK-UUID] ro  quiet splash $vt_handoff
    initrd  /boot/initrd.img-4.13.0-32-generic
}

# Working entry (disk UUID has been replaced)
menuentry 'Ubuntu, with Linux 4.13.0-21-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.13.0-21-generic-advanced-[DISK-UUID]' {
    recordfail
    load_video
    gfxmode $linux_gfx_mode
    insmod gzio
    if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
    insmod part_gpt
    insmod ext2
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root  [DISK-UUID]
    else
      search --no-floppy --fs-uuid --set=root [DISK-UUID]
    fi
    echo    'Loading Linux 4.13.0-21-generic ...'
    linux   /boot/vmlinuz-4.13.0-21-generic.efi.signed root=UUID=[DISK-UUID] ro  quiet splash $vt_handoff
    echo    'Loading initial ramdisk ...'
    initrd  /boot/initrd.img-4.13.0-21-generic
}

System Info:

• Ubuntu 17.10
• Intel® Core™ i7-5930K CPU @ 3.50GHz × 12
• GeForce GTX 1080/PCIe/SSE2
• Gnome 3.26.2
• OS Type 64-bit
• Primary Disk m.2 SSD
• Grub 2.02~beta3-4ubuntu7.1

Answer 1

I just ran into the same issue. It was because my initial ramdisk was too large. I don't know how big is too big, but my new kernel's initrd was about 10 times bigger than the default ones from Ubuntu.

The solution was to strip the unneeded symbols from the kernel modules. I am not a kernel developer, so symbols in the modules are of no use to me. I found this thread that provided a quick way to strip the symbols: https://unix.stackexchange.com/questions/270390/how-to-reduce-the-size-of-the-initrd-when-compiling-your-kernel

Once that was done, I rebuilt the initrd and it was close to the same size as the default initrd images. Then I ran update-grub, and then I was able to boot to the new kernel.