Booting from a USB flash drive
The image has to be written verbatim to the USB flash drive for it
to be bootable on UEFI and BIOS systems. Here are the recommended
tools to do that.
Creating bootable USB flash drive with a graphical
tool
Etcher is a popular and user-friendly tool. It works on Linux,
Windows and macOS.
Download it from
balena.io,
start the program, select the downloaded NixOS ISO, then select
the USB flash drive and flash it.
Etcher reports errors and usage statistics by default, which can
be disabled in the settings.
An alternative is
USBImager,
which is very simple and does not connect to the internet.
Download the version with write-only (wo) interface for your
system. Start the program, select the image, select the USB flash
drive and click Write.
Creating bootable USB flash drive from a Terminal on
Linux
Plug in the USB flash drive.
Find the corresponding device with lsblk.
You can distinguish them by their size.
Make sure all partitions on the device are properly unmounted.
Replace sdX with your device (e.g.
sdb).
sudo umount /dev/sdX*
Then use the dd utility to write the image
to the USB flash drive.
sudo dd if=<path-to-image> of=/dev/sdX bs=4M conv=fsync
Creating bootable USB flash drive from a Terminal on
macOS
Plug in the USB flash drive.
Find the corresponding device with
diskutil list. You can distinguish them by
their size.
Make sure all partitions on the device are properly unmounted.
Replace diskX with your device (e.g.
disk1).
diskutil unmountDisk diskX
Then use the dd utility to write the image
to the USB flash drive.
sudo dd if=<path-to-image> of=/dev/rdiskX bs=4m
After dd completes, a GUI dialog The
disk you inserted was not readable by this computer will
pop up, which can be ignored.
Using the rawrdiskX device
instead of diskX with dd completes in minutes
instead of hours.
Eject the disk when it is finished.
diskutil eject /dev/diskX