grub2 – GRUB issues – How to get back to windows boot manager

So I am dual-booting Windows and Ubuntu 16.04, and I have the Ubuntu partition encrypted. After updating yesterday my GRUB won’t load. I tried using a live USB with boot-repair-disk but it wasn’t able to do anything (possible due to the encryption??)

I don’t have anything important saved on the linux partition but I do need access to Windows and I don’t want to lose the files I have saved there. Is there a way to get windows boot manager to load? Or any other ways to fix GRUB for the time being? I don’t mind deleting the linux partition and reinstalling Ubuntu (and maybe following a more up-to-date page for encrypting it.)

redhat – Does the BootHole Vulnerability Effect Grub1 or Only Grub2?

I’ve been doing some reading on BootHole to help understand our attack surface and see everything talking about GRUB2, but nothing about GRUB “Legacy” or GRUB1. Wondering if it has tested against this older version of the bootloader. Older distros (RHEL5 & 6) used GRUB1 and am just curious if they have been proven unaffected by BootHole. I can’t be the only one thinking this, but haven’t been able to find anyone talking about it.

grub2 – How to fix a grub boot error : “symbol ‘grub_calloc’ not found

just ran the latest batch of updates on 20.04 ( Xubuntu ), now I’m getting a grub error :

symbol ‘grub_calloc’ not found

I’m dropped into the ‘grub rescue’ shell, but have no idea what to do there that might be useful. To me, ‘symbol not found’ implies some sort of build error with the grub package, but I don’t really know how grub works. I noticed that this update also included ‘firmware’, not sure if that could be related. Is my best bet just to boot from a live CD and see if I can roll back grub somehow ?

grub2 – How to pass custom variables into bash from grub?

I use a custom iso for installing linux on virtual machines on a dedicated server. My only issue is I need to recompile a new iso for every new machine because the IP and mac address change, and the network must be set up manually by a script.

Is there a way I can boot the iso and pass the ip and mac address from grub and then retrieve those variables from bash?

grub2 – Can You Change or Control the Dual Boot Screen

I made my Win XP system a dual boot with Ubuntu Desktop 20.04. The little screen (I don’t know what you call it) that comes up giving you the options of booting into Ubuntu or Windows appears in the top left corner of my monitor and the font is too small to read easily, and it disappears too quickly. Is there a way to make the font bigger and give me more time to select an option? Actually I have about 5 options:))


grub2 – Alert! /dev/sda5 does not exist. Dropping to a shell

I installed Ubuntu 20.04 on my laptop but when I start it’s shown this error

ALERT! /dev/sda5 does not exist. Dropping to a shell

BusyBox v1.30.1 (Ubuntu v1:1.30.1-4ubuntu6) built-in shell (ash)
Enter help for a list of built-in commands.


I tried to fix following some steps like to restore grub and mount the correct ‘section’ but I have the same problem.

I also reinstalled the operational system but nothing changes.

grub2 – Why does the EFI boot loader backup fail?

I am experimenting with EFI bootloaders and there is something I don't understand.
That is the situation:

  1. I compiled by scratch grub2.

  2. Formatted a USB drive with an EFI partition and placed the obtained
    bootx64.efi and grub.cfg in / EFI / BOOT. USB drives boot successfully.

  3. If you replicate point 2 using an SSD, the system won't boot!

  4. I discovered that putting bootx64.efi in Microsoft / Boot / bootmgfw.efi makes the system bootable.

So my question (s):

Is it possible that USB drives have a different backup than hard drives?
Or why doesn't my system boot from SSD with /EFI/BOOT/bootx64.efi backup?

Thank you,


grub2 – Trackpad freezes after suspending Ryzen 2500U

I am using a Huawei Matebook 14D with AMD Ryzen 2500U with Ubuntu 19.10. My Trackpad freezes every time I wake up my system from sleep. You also experience some random keyboard and system crashes (although not as often as the touchpad crashes). This is what my grub file looks like (/ etc / default / grub):

GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="iommu=soft processor.max_cstate=1 i8042.reset i8042>

All changes made to the grub file come from various random sources on the Internet. Please help!

grub2 – Does os-prober work well for Ubuntu 18 (kernel v5)?

os-prober in an instance of Ubuntu 18 with Google Compute Engine (image: ubuntu-minimal-1804-bionic-v20200220 – "Canonical, Ubuntu, 18.04 LTS Minimal, minimal bionic image amd64 built in 2020-02-20") returns an unexpected partition:

# os-prober
/dev/sda1:Ubuntu 18.04.4 LTS (18.04):Ubuntu:linux
# uname -a
Linux pfuntner-gcp-ubuntu1804 5.0.0-1031-gcp #32-Ubuntu SMP Tue Feb 11 03:55:48 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
# cat /etc/os-release
VERSION="18.04.4 LTS (Bionic Beaver)"
PRETTY_NAME="Ubuntu 18.04.4 LTS"
# mount
/dev/sda1 on / type ext4 (rw,relatime)
devtmpfs on /dev type devtmpfs (rw,relatime,size=1885000k,nr_inodes=471250,mode=755)
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,noexec)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,nodev,mode=755)
tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k)
tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755)
cgroup on /sys/fs/cgroup/unified type cgroup2 (rw,nosuid,nodev,noexec,relatime)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,name=systemd)
pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)
efivarfs on /sys/firmware/efi/efivars type efivarfs (rw,nosuid,nodev,noexec,relatime)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)
cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,relatime,hugetlb)
cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,net_cls,net_prio)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)
cgroup on /sys/fs/cgroup/rdma type cgroup (rw,nosuid,nodev,noexec,relatime,rdma)
cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpu,cpuacct)
cgroup on /sys/fs/cgroup/pids type cgroup (rw,nosuid,nodev,noexec,relatime,pids)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,perf_event)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=28,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=10640)
mqueue on /dev/mqueue type mqueue (rw,relatime)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime,pagesize=2M)
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
fusectl on /sys/fs/fuse/connections type fusectl (rw,relatime)
configfs on /sys/kernel/config type configfs (rw,relatime)
/dev/sda15 on /boot/efi type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
/var/lib/snapd/snaps/core_8592.snap on /snap/core/8592 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/google-cloud-sdk_118.snap on /snap/google-cloud-sdk/118 type squashfs (ro,nodev,relatime,x-gdu.hide)
lxcfs on /var/lib/lxcfs type fuse.lxcfs (rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,relatime)
tmpfs on /run/user/1008 type tmpfs (rw,nosuid,nodev,relatime,size=377836k,mode=700,uid=1008,gid=1009)

The output of os-prober It causes a problem when I try to modify the boot and run parameters update-grub why not all linux statements in /boot/grub/grub.cfg I have the options that I am trying to present. I know /etc/grub.d/30_os-prober is generating the extra linux statements and what can I use GRUB_DISABLE_OS_PROBER to disable the use of the script, but I don't think I should do it.

Google support confirms that several operating systems are not possible with an instance of GCE and I do not expect os-prober to return any output.

grub2: how to make the grub menu appear instead of booting directly in Windows 10

  • HP Envy X360 with SecureBoot / UEFI boot loader
  • I ran the boot repair from a USB stick
  • I tried to change the boot order in BIOS (I see Windows and ubuntu but I can't select and save ubuntu)
  • With F9 at boot I can see the ubuntu menu, I can also successfully boot to W10 or ubuntu 18.04
  • I can also see and restart the grub menu from Windows with super-r, ms-settings: recovery, Restart Now and choose boot from External, choose ubuntu

So I guess this is a question from HP, as well as one from ubuntu. I will review your discussion groups and, if I get an answer, I will report here. I can also try to erase all secure BIOS boot keys to see if that allows me to select grub as first in the boot order.

TIA for any advice or ideas that HP owners may have.