NixOS rescue

I managed to rescue my existing NixOS installation on a dual-boot Asus laptop with Windows, using a Sandisk MobileMate SD-card reader and a 4GB microSD card.

I flashed the NixOS graphical .iso image on the microSD card using Rufus. Then, after inserting it in the MobileMate into the USB drive of the Asus laptop, I booted it and immediately pressed F2. This allowed me to enter BIOS, and it then showed a Boot option for the Sandisk device. I had to reboot the machine manually once again, but then it showed NixOS.

In NixOS, I opened a terminal window and did the following steps:

1. sudo su -
2. fdisk -l to find the EFI partition (via)
3. mkdir -p /mnt/boot ; mount /dev/$THE_EFI_PARTITION /mnt/boot
4. mv /mnt/boot/EFI/Microsoft{,.bak} (via)
5. Reboot
6. NixOS image choice GRUB menu should show up - pick as appropriate.
7. In NixOS, assuming /dev/$THE_EFI_PARTITION is mounted at /boot, revert back the EFI contents: sudo mv /boot/EFI/Microsoft{.bak,}
8. Shutdown, then boot again, but hold F2 pressed when booting.
9. In BIOS, adjust the boot order, to put “EFI Partition…” first (this is the NixOS).