Dual‑Boot Playbook — Lenovo T490s

Windows 11 + Arch/Omarchy (2025)

This is the result of a lot of back and forth with ChatGPT o3 along with my own troubleshooting. While this contains a fair amount of detail, I would probably recommend starting with this as part of your prompt and have ChatGPT walk you through it. I don't totally understand why Linux Boot Manager didn't install, or why the partition references got screwed up when I moved them around when resizing the ESP. Regardless, this works!

0 Prerequisites

Item	Notes
ISOs	`gparted-live.iso`, `archlinux-x86_64.iso`
USB writer	KDE ISO/USB Writer or Rufus
Goal layout	ESP 512 MB FAT32 → MSR 16 MB → C: NTFS → Arch ext4/btrfs

1 Shrink Windows C: & disable trouble‑makers

Win + X → Disk Management → C: → Shrink Volume → free ≥ 60 GB
Suspend BitLocker — Control Panel ▸ BitLocker Drive Encryption ▸ Suspend
Disable Fast Startup — Power Options ▸ Choose what the power buttons do ▸ untick
Write GParted USB — GParted ISO → KDE Writer

2 Re‑arrange partitions in GParted

Boot USB (Enter → F12 → USB)
Delete Windows recovery partition at end (≈ 900 MB NTFS)
Drag‑move C: right; unallocated space now sits between ESP and C:

Resize ESP (FAT32) 100 MB → 512 MB
If resize fails (“fat32 resize failed”):

# Ctrl+Alt+F2 to TTY in GParted Live
mkdir /tmp/efi && mount /dev/nvme0n1p1 /tmp/efi
cp -a /tmp/efi /tmp/efibak
mkfs.fat -F32 /dev/nvme0n1p1
cp -a /tmp/efibak/* /tmp/efi/
umount /tmp/efi

Apply → Reboot to Windows (confirm C: boots)

3 Create Arch USB & boot it

Write Arch ISO → USB
Reboot → Enter → F12 → choose Arch stick → first “UEFI” entry

4 Connect to Wi‑Fi (live ISO)

iwctl
device list                      # note iface (e.g. wlp0s20f3)
station <IFACE> connect "SSID"
exit
ping -c3 archlinux.org

5 Install with `archinstall` (manual disks)

Disk configuration ▸ Partitioning ▸ Manual
Create root in free space
- FS ext4 or btrfs
- Format Yes • Mount /
Select ESP (nvme0n1p1) → Format No → Mount /boot
Write & Exit; table shows / and /boot
Bootloader = systemd‑boot
Create user (wheel) & pick extra pkgs (wget, …)
Install → wait ~5 min → Reboot (remove USB)

6 Fix Windows boot‑loop (if it happens)

HTML table used so multi‑line code blocks render correctly.

Step	CLI command / Action
Enter WinRE	Let Windows fail to boot twice – on the third restart it will show Automatic Repair. Choose `Advanced options → Troubleshoot → Command Prompt`.
Identify letters	diskpart list vol exit Note: EFI (FAT32) is typically `S:`; Windows (NTFS) is `C:` (may be `D:`).
Repair & rebuild	chkdsk C: /f bcdboot C:\Windows /s S: /f UEFI bootrec /scanos bootrec /rebuildbcd bootrec /fixboot
BitLocker unlock (only if prompted)	manage-bde -unlock C: -RecoveryPassword <48-digit-key> manage-bde -protectors -disable C:
Exit & reboot	Type `exit` then choose Continue. Windows should now boot normally.

7 Add “Linux Boot Manager” (if missing)

# Boot Arch USB again
mount /dev/nvme0n1p4 /mnt
mount /dev/nvme0n1p1 /mnt/boot
arch-chroot /mnt
bootctl install
efibootmgr --create   --disk /dev/nvme0n1 --part 1   --label "Linux Boot Manager"   --loader '\EFI\systemd\systemd-bootx64.efi'
exit
umount -R /mnt && reboot

(Optional) BIOS F1 ▸ Startup ▸ Boot ▸ move Linux Boot Manager above Windows.

8 Post‑install polish

sudo pacman -Syu

# (btrfs only)
sudo pacman -S snapper
sudo btrfs subvolume create /@snapshots

Install Omarchy:

wget -qO- https://omarchy.org/install | bash

Appendix A — Final partition map

nvme0n1p1  512M  FAT32      /boot
nvme0n1p2   16M  MSR
nvme0n1p3  …    NTFS       C:nvme0n1p4  …    ext4/btrfs /

Appendix B — Common pitfalls

Symptom	Fix
Arch boots to blinking cursor	Boot USB → `arch-chroot` → fix `/etc/fstab`
Windows missing in systemd‑boot	`bootctl update && bootctl install`
Windows update deletes Linux entry	Re‑run §7 or disable Fast Startup

End of checklist – enjoy your dual‑boot T490s.

hisnameisjimmy/lenovo-dual-boot-arch-omarchy.md