.. include:: /substitutions.rst

.. _bootable-sd-card:

Creating a Bootable NuttX SD Card From Scratch
==============================================

To create a bootable Micro SD card, here are the steps:

#. Format the card with a FAT filesystem

   Under macOS, you can use Disk Utility. Under Linux, here are the commands (replace
   ``/dev/sdb`` with the path to your SD Card device:

    .. code-block:: bash

       $ sudo parted /dev/sdb --script -- mklabel JUPITERNANO
       $ sudo parted /dev/sdb --script -- mkpart primary fat32 1MiB 100%
       $ sudo mkfs.vfat -F32 /dev/sdb1

#. Copy the U-Boot binary and U-Boot environment files to the SD Card.

   Copy ``BOOT.BIN``, ``u-boot.bin`` and ``uboot.env`` from a working bootable NuttX SD Card. I'll post
   instructions for building them using the
   `Jupiter Nano Tools <https://github.com/starcat-io/jupiter-nano-tools>`_ later.

   ``BOOT.BIN`` is the `at91bootstrap <https://github.com/linux4sam/at91bootstrap>`_ second stage bootloader. 
   `U-Boot <https://www.denx.de/wiki/U-Boot>`_ is the third stage bootloader. The first stage is the internal
   ROMBOOT program stored on the SAMA5D27C chip.

#. Copy the ``nuttx.bin`` binary to the SD Card

    .. code-block:: bash

       $ cp nuttx.bin /media/your_user_name/JUPITERNANO/

Now you can take the SD Card out of the reader, put it into the Jupiter Nano,
and boot it.