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{{Applies To Bora}}
{{Applies To BoraX}}
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<section begin=BTELKBELK/>
== Standalone boot==
This document shows some examples related to configuring Bora/BoraX/BoraLite for standalone operativity.
We'll explain how to program and configure a [[:Category:BoraXBORA Xpress SOM|BoraXBORA Xpress]]-based system to boot in standalone mode, without the need of a system microSD card or an NFS server. Only the flash memories available on the SoM itself will be used to store persistently all the software required.
The examples here documented are valid for [[:Category:BoraBORA SOM|BoraBORA]] and for [[:Category:BoraLiteBORA Lite SOM|BoraLiteBORA Lite]] as well.
{{ImportantMessage|text=It is worth remembering that the examples shown in this article don't make use of any image script. This technique is used by the bootable microSD card delivered along with the kit, instead. For more details, please refer to [[Working_with_the_Yocto_build_system#bootscript|this section]].}}
This is a common step for both booting options.
* Boot the system via SD or NFS as described into the [[System_boot_and_recovery_via_microSD_card_(BORA_SOM/BELK-L/Development/BXELK)How_to_create_a_bootable_microSD_card|System boot and recovery via microSD card]] and [[Booting_the_system_via_NFS_(BORA_SOM/BELK-L/General/BXELK)Booting_from_NFS|Booting the system via NFS]]
* By default, the NAND is already partitioned to allow booting from NAND-only (see next section) and, thus, some partitions are reserved for FSBL, U-boot and kernel images. Here we won't modify this default configuration. The [[Memory Tecnology Device (MTD)|MTD]] partitions can be dumped with <code>/proc/mtd</code> (the partition's name should be self-explanatory)
==== Program the root filesystem in NAND flash ====
This step can be followed in the same way as described [[Standalone_boot_(BORA_SOM/BELK-L/Deployment/BXELK)Standalone_boot#Program_the_root_filesystem_in_NAND_flash | before]]
==== Program the boot images in NAND flash from U-Boot ====
To setup the desired standalone configuration, several operations need to be carried out. They are detailed in the following sections. It is assumed that the SOM can boot from the NOR flash. If not, please see [[BORA_SOM/BELK-L/Deployment/Restoring_U-Boot_on_SPI_NOR_flash_(BELK/BXELK)Boot_on_NOR_flash|this page]].
=====Testbed=====
*<code>mtd0</code>, <code>mtd1</code>, and <code>mtd2</code> are significantly larger than the files they store used in this example. This allows having a spare room to store larger images. For the sake of simplicity, U-Boot was configured to read the whole partitions (see how the <code>loadunand</code>, <code>loadfdtnand</code>, and <code>loadfpga2</code> variables are defined). Obviously, this affect the overall boot time negatively. To optimize it, these variables have to be changed in order to read just the required amount of data according to the size of the actual stored files.
*As stated previously, the root filesystem is <code>initramfs</code> and thus not persistent. Consequently, every time the system boots, the directory <code>/mnt/data3</code> must be created before mounting the ''UBIFS'' file system stored in the NAND flash.
<section end=BTELKBELK/>