add post: Fix: Rebuilding Windows EFI

1 files changed, 151 insertions, 0 deletions

diff --git a/src/content/blog/repairing-windows-efi.md b/src/content/blog/repairing-windows-efi.md
new file mode 100644
index 0000000..e9918b3
--- /dev/null
+++ b/src/content/blog/repairing-windows-efi.md
@@ -0,0 +1,151 @@
+---
+title: 'Fix: Rebuild Windows EFI'
+description: 'Rebuilding the Windows EFI partition, dual-boot with systemd-boot on a seperate drive'
+pubDate: 'May 5 2024'
+---
+
+If I had a dollar for every time that I somehow overwrote or deleted the Windows EFI boot partiton while toying with something on Linux I'd have $3 (which isn't a lot but having it happen 3 times already is pretty annoying). If you ask some enthusiasts, this is secretly a blessing in disguise since you're technically one step closer to escaping the grasp of Microsoft. However like many others who choose to dual-boot, I prefer to keep my Windows installation around in case I need it for some specific use case.
+
+I'm not the most well-versed when it comes to the whole Windows IT stuff, in fact I think most of my knowledge about how to even use the Windows shell has completely gone out the Window. This post serves as a quick guide for how to rebuild the EFI partition that contains the bootloader, as well as how to re-add the Windows to the systemd-boot menu.
+
+# Diagnosis
+Depending on the order in which you installed Windows and Linux, the location of where your EFI partition actually is may differ. On my setup, I have Windows on my first drive and Linux on my second. My EFI partition with my current bootloader lives on my second drive which persumably also included my Windows 11 bootloader.
+
+So when I went and wiped my disk, this removed all files associated on that drive about my previous install (since I basically reformatted everything), and among that of course was the Windows bootloader meaning I effectively had no way to boot back into Windows
+
+Chances are that if you find that the Windows boot option is missing, you're in the same boat.
+
+# Rebuld the EFI Partition
+1. Flash the Live Media ISO to a USB
+Use Balena Etcher or something similar to flash the Disk Image ISO to a USB drive.
+
+2. Reboot into the Live USB
+For some reason you have to press something (literately any key) on your keyboard after selecting to boot into the media, or else it'll just kick you back into the UEFI menu.
+
+3. Select `Repair Your Computer` and `Advanced Options`. Launch the `Command Prompt`
+
+Launch the diskpart utility
+```
+diskpart
+```
+
+Select the disk with Windows on it:
+```
+select disk X
+```
+
+It helps to list the disks and examine the partitions to differentiate between them.
+Usually if there's like a 20gb or so Recovery/Reserved partition on a drive that'll be the one where Windows is on.
+```
+list disk
+select disk X
+list part
+```
+
+**Make sure you've selected the disk with Windows on it!**
+
+4. Shrink a partition for the new EFI
+I'd suggest shrinking the partition that holds your current Windows files. Usually it'll have the type `Primary`.
+
+It'll look something like that's below
+```
+Partition ### Type     Size    Offset
+------------- -------- ------- ------
+Partition 1   Primary  200 GB   18 KB
+Partition 2   Reserved 20 GB    17 KB
+```
+
+Select the partition you want to shrink from. (or don't if you have 500MB of freespace somehow)
+```
+select part X
+```
+Then shrink it
+```
+shrink desired=500
+```
+
+5. Create the EFI partition
+The drive letter can be whatever you want, as long as its not already in use (Y is a good one)
+```
+create partition efi
+format fs=fat32 quick
+assign letter=Y
+```
+
+Exit diskpart with
+```
+exit
+```
+
+6. Install the bootloader
+The drive letter below `Y` will be replaced with whatever letter you chose in the last step
+```
+bcdboot c:\Windows /s Y: /f ALL
+```
+
+Now reboot and see if you can get into Windows
+
+# Re-add Windows to systemd-boot
+Ok assuming you can get into Windows now, we want to re-add the option for Windows into systemd-boot.
+
+Go ahead and boot into Linux and find the new created EFI partition
+```bash
+lsblk -f
+```
+Look for something that's `vfat FAT32`
+- If you are using an ASUS computer like me, ignore the `MYASUS` partition
+
+There should be 1 on each drive, go ahead and note the names of these 2 down, as well as which one is for which OS
+```
+Example: (the name is the first column of the output)
+nvme0n1p1
+nvme1n1p1
+```
+
+1. Mount the EFI partitions
+First create the mount points for both partitions
+```bash
+sudo mkdir /mnt/arch_efi
+sudo mkdir /mnt/efi
+```
+You can name them whatever, but I'll use `arch_efi` to indicate the Linux EFI partition and `efi` for Windows
+
+Mount both partitions
+```bash
+sudo mount /dev/your_drive_name_linux /mnt/arch_efi
+sudo mount /dev/your_drive_name_windows /mnt/efi
+```
+
+2. Find the `Microsoft` folder in Windows EFI
+You can also open Dolphin or whatever file manager as root if it helps
+
+```bash
+cd /mnt/efi
+ls
+```
+There should be a folder named `EFI`, and inside it there should be a Microsoft folder
+
+Once you have confirmed this, go ahead and copy this folder over to the EFI folder on `/mnt/arch_efi`
+
+```bash
+sudo cp -r /mnt/efi/EFI/Microsoft /mnt/arch_efi/EFI/
+```
+
+Unmount everything
+```bash
+sudo umount /mnt/efi
+sudo umount /mnt/arch_efi
+```
+
+3. Update systemd-boot configuration
+```bash
+sudo bootctl update
+```
+This is usually done automatically though
+
+Now go ahead and reboot and you should see the Windows option in systemd-boot again.
+
+
+
+
+