SDAA437
July 2026
TDA4VE-Q1
1
Abstract
Trademarks
1
Introduction
1.1
Motivation
1.2
Scope
1.3
Target Boot Architecture
2
Background
2.1
J721S2 Boot Flow
2.2
OSPI NOR Flash Overview
2.3
UBI and UBIFS Overview
3
OSPI Flash Layout
3.1
Partition Layout
3.2
Bootloader Partitions
3.3
Root Filesystem Partition
4
Flashing Boot Components
4.1
Boot Components Overview
4.2
Identifying OSPI MTD Partitions
4.3
Flashing Boot Components into OSPI NOR Flash
4.4
Verifying Boot Components
5
Creating a UBIFS Root Filesystem
5.1
Preparing the RootFS Partition
5.2
Creating a UBI Device
5.3
Creating a UBIFS Volume
5.4
Verifying UBIFS Operation
6
Storing Linux Boot Artifacts in UBIFS
6.1
Mounting the UBIFS Root Filesystem Volume
6.2
Creating the Root Filesystem Structure with BusyBox
6.3
Verifying BusyBox Execution
6.4
Creating BusyBox Command Links
6.5
Creating the init Script
6.6
Testing the Root Filesystem Using chroot
6.7
Copying the Linux Kernel Image and DTB
7
Configuring Linux Boot from UBIFS
7.1
Configuring Boot Arguments
7.2
Loading the Kernel and DTB from UBIFS
7.3
Testing Linux Boot
7.4
Creating a Reusable Boot Command
8
Booting Linux Entirely from OSPI NOR Flash
8.1
Automating the Boot Sequence in U-Boot
8.2
End-to-End Boot Flow
9
Summary
10
References
Application Note
Linux Boot from OSPI NOR Flash Without eMMC on TI J721S2