setzer22 · November 28, 2024 21:18 · Aug 22, 2017 · Aug 22, 2017 · Aug 22, 2017 · Aug 22, 2017
diff --git a/README.md b/README.md
@@ -1,4 +1,4 @@
-# Reboot into windows command
+# Linux command to hibernate and then reboot into a different OS
 
 In this document I describe my setup about how to add a menu shortcut that will hibernate and reboot the system into a different OS (in my case, Windows), and then restore linux on the next reboot.
 

diff --git a/README.md b/README.md
@@ -82,7 +82,7 @@ sudo systemctl hibernate
 Note that the script needs to be run as root. You can work around this by not requiring sudo password for your user just for this three commands.
 
 ## Sources:
-  - [https://www.freedesktop.org/wiki/Software/systemd/systemd-boot/]
-  - [https://wiki.archlinux.org/index.php/Unified_Extensible_Firmware_Interface#Requirements_for_UEFI_variable_support]
-  - [http://www.johnhawthorn.com/2011/03/hibernate-with-reboot/]
-  - [https://www.freedesktop.org/software/systemd/man/sleep.conf.d.html]
+  - https://www.freedesktop.org/wiki/Software/systemd/systemd-boot/
+  - https://wiki.archlinux.org/index.php/Unified_Extensible_Firmware_Interface#Requirements_for_UEFI_variable_support
+  - http://www.johnhawthorn.com/2011/03/hibernate-with-reboot/
+  - https://www.freedesktop.org/software/systemd/man/sleep.conf.d.html
diff --git a/README.md b/README.md
@@ -67,6 +67,20 @@ The script in this folder will be run after hibernation with $1="post" and $2="h
 
 Now, after runing `enable-hibernate-reboot` the computer will reboot after hibernation, but only once.
 
+# Wrapping up
+
+Finally, we can set up a wrapper script to glue everything we've done so far:
+
+```
+#!/bin/bash
+
+sudo /path/to/enable-hibernate-reboot
+sudo efibootmgr --bootnext 0000
+sudo systemctl hibernate
+```
+
+Note that the script needs to be run as root. You can work around this by not requiring sudo password for your user just for this three commands.
+
 ## Sources:
   - [https://www.freedesktop.org/wiki/Software/systemd/systemd-boot/]
   - [https://wiki.archlinux.org/index.php/Unified_Extensible_Firmware_Interface#Requirements_for_UEFI_variable_support]

diff --git a/README → README.md b/README → README.md
diff --git a/README b/README
@@ -0,0 +1,74 @@
+# Reboot into windows command
+
+In this document I describe my setup about how to add a menu shortcut that will hibernate and reboot the system into a different OS (in my case, Windows), and then restore linux on the next reboot.
+
+For this, I'll be using Arch Linux with systemd-boot as my boot manager, but in practice any bootloader that handles the LoaderEntryOneShot (a.k.a. BootNext) efivar should work.
+
+**NOTE** It is advisable to not do this with window's fast boot feature active, since alternating the hibernation of two systems can cause shared partitions to get corrupted. However, if additional steps are taken in order to ensure the shared partition are unmounted before reboot, or no partitions are shared between the two OSs, this can be made to work with fastboot enabled which should give quite a boost in Windows' startup time.
+
+## Set the LoaderEntryOneShot/BootNext EFI variable
+
+First, we want to set this efi variable in order to tell the system that a different OS should be loaded on next boot, and only that next boot. In systemd-boot this means that not even the OS selection screen will be shown and the selected OS will be loaded directly.
+
+This can be accomplished using `efibootmgr`
+
+To show the current boot entries:
+
+```
+# efibootmgr
+```
+
+Example output:
+
+```
+BootCurrent: 0002
+Timeout: 1 seconds
+BootOrder: 0002,0000,0005,0006
+Boot0000* Windows Boot Manager
+Boot0002* Linux Boot Manager
+Boot0005* UEFI: IP4 Qualcomm Atheros PCIe Network Controller
+Boot0006* UEFI: IP6 Qualcomm Atheros PCIe Network Controller
+```
+
+Here, we get the hex code of the OS we want to boot, in our case, 0000. Then, we can use efibootmgr to set the LoaderEntryOneShot efivar with `--bootnext`
+
+```
+efibootmgr --bootnext 0000
+```
+
+Now, upon reboot, entry 0000 will be loaded automatically, and the variable will be reset on the next boot.
+
+## Hibernate and then restart
+
+The `s2disk` command, available as part of the `uswsusp` (AUR) package can hibernate the system, and has a flag which allows us to set the shutdown method to reboot just on a single hibernation. However, `s2disk` for some reason didn't work on my machine, so I made an equivalent (although less robust) systemd-based configuration.
+
+First, a script `enable-hibernate-reboot` stored in my $PATH
+
+```
+#!/bin/bash
+
+if [ -f /etc/systemd/sleep.conf ]; then
+    sudo mv /etc/systemd/sleep.conf /etc/systemd/sleep.conf.bak
+fi
+sudo printf "[Sleep]\nHibernateMode=reboot" > /etc/systemd/sleep.conf
+```
+
+And also, a `disable-hibernate-reboot` stored at the special folder `/usr/lib/systemd/system-sleep`:
+
+```
+#!/bin/bash
+
+if [ -f /etc/systemd/sleep.conf.bak ] && [ $1 == "post" ] && [ $2 == "hibernate" ]; then
+  mv /etc/systemd/sleep.conf.bak /etc/systemd/sleep.conf
+fi
+```
+
+The script in this folder will be run after hibernation with $1="post" and $2="hibernate" (see sleep.conf.d manpage) when resuming from hibernation, thus restoring the old sleep.conf. Note that for the hibernation that will reboot to windows, any configuration you had previously set up in `/etc/systemd/sleep.conf` (if any) will be disabled.
+
+Now, after runing `enable-hibernate-reboot` the computer will reboot after hibernation, but only once.
+
+## Sources:
+  - [https://www.freedesktop.org/wiki/Software/systemd/systemd-boot/]
+  - [https://wiki.archlinux.org/index.php/Unified_Extensible_Firmware_Interface#Requirements_for_UEFI_variable_support]
+  - [http://www.johnhawthorn.com/2011/03/hibernate-with-reboot/]
+  - [https://www.freedesktop.org/software/systemd/man/sleep.conf.d.html]
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