1 Introduction

NXP has released a set of OTA projects based on MCU on Github. These

projects support the i.MXRT series and related security functions, which have

attracted widespread attention from users. However, these projects are based

on EVK development board of NXP. The capacity of the onboard Flash

determines the storage structure of the entire OTA project. Therefore, the OTA

storage structures vary from each other due to the differences in the capacity

of Flash. This application note introduces the default storage structure and

summarizes some latest experiences while supporting customers. To replace

the Flash, complete the configuration of the OTA projects faster.

2 OTA storage structure overview

The entire OTA consists of SBL and SFW. You can download them from:

• SBL: https://github.com/NXPmicro/sbl

• SFW: https://github.com/NXPmicro/sfw

The onboard flash is an 8 MB QSPI Flash, so 8 MB of space is allocated. Figure 1 shows the storage structure of the entire OTA.

OTA includes SBL (Secure Bootloader), OTA Flag Data, Slot 1, Slot 2, and Customer Data areas.

Figure 1. Storage structure

2.1 Secure BootLoader (SBL)

After the chip POR is started, SBL determines the execution of programs stored in Slot 1 or Slot 2 according to the information of

OTA Flag Data. SBL supports program verification, revert, and other functions.

The remap function needs 4 kB alignment.

NOTE

Table 1 illustrates the common address space allocation of SBL.

Contents

1 Introduction......................................1

2 OTA storage structure overview......1

2.1 Secure BootLoader (SBL)............1

2.2 OTA Flag Data.............................2

2.3 Slot 1 and Slot 2.......................... 2

2.4 Customer Data.............................2

3 Example: How to customize a storage

structure.......................................... 3

3.1 Overview......................................3

3.2 Address space allocation of

specific demands......................... 3

4 Revision history...............................5

AN13505

OTA Storage Structure on RT1010

Rev. 0 — 20 January 2022

Application Note

Table 1. SBL memory map

　 Function Add_Start Add_End

SBL (1 MB - 4 kB)

OTFAD 0x60000000 0x600003FF

m_boot_hdr_conf_start 0x60000400 0x60000FFF

m_boot_hdr_ivt_start 0x60001000 0x6000101F

m_boot_hdr_conf_start 0x60001020 0x6000102F

m_boot_hdr_dcd_start 0x60001030 0x60001FFF

SBL_Code_Vector_Start 0x60002000 0x600FEFFF

2.2 OTA Flag Data

OTA Flag Data area is used to store some flag information during the process of OTA update. According to the flag information

of SBL, the image can be updated, reverted, and jumped to the corresponding slot running program. Table 2 shows the address

space allocation of this area.

Table 2. OTA Flag Data memory map

　 Function Add_Start Add_End

Reserved (4 kB - 32 B) Reserved 0x600FF000 0x600FFFDF

OTA Flag Data (32 B) OTA Flag 0x600FFFE0 0x600FFFFF

2.3 Slot 1 and Slot 2

Slot 1 and Slot 2 are used to store the application program. The remap function can switch between Slot 1 and Slot 2, which

requires 4 kB alignment. Slot 1 and Slot 1 each has 1 MB space. Table 3 shows the common address space allocation of Slot 1

and Slot 2.

Table 3. Slot 1 and Slot 2 memory map

　 Function Add_Start Add_End

Slot 1 (1 MB)

Image Header 0x60100000 0x601003FF

Application Image 0x60100400 0x601FFFFF

Slot 2 (1 MB)

Image Header 0x60200000 0x602003FF

Application Image 0x60200400 0x602FFFFF

2.4 Customer Data

Customer Data is used to store the information of customers (optional, not compulsory). Table 4 shows the address space

allocation of customer data area.

Table 4. Customer Data memory map

　 Function Add_Start Add_End

Customer Data (5 MB) Customer Data 0x60300000 0x607FFFFF

NXP Semiconductors

OTA storage structure overview

OTA Storage Structure on RT1010, Rev. 0, 20 January 2022

Application Note 2 / 6