Guidelines for Bootloader Firmware with MCUBoot and External QSPI Flash

Question

Hi, 
 Could someone please provide any available guidelines for Bootloader Firmware using MCUBoot and External QSPI Flash based on the following specifications? 
 
 MCU : R7FA4M3AFCFP 
 IDE : e2Studio 
 FSP Version : V4.2.0

Thanks, Parth

AZ-Renesas · Answer

Hello, 
 Please check the below application note and sample code which is using the MCUboot module on EK-RA4M3 with external QSPI flash as the secondary image storage area. 
 https://www.renesas.com/en/document/apn/booting-encrypted-image-ra4-using-mcuboot-and-qspi-application-project 
 www.renesas.com/.../booting-encrypted-image-using-mcuboot-and-qspi-application-project

AZ-Renesas · Answer

For EK boards with QSPI flash on board, after booting, the QSPI device is typically place in XIP mode. MCU can read directly from it(memory mapped). That means you can jump into codes in qspi area and begin execution from there. This has not been tested with MCUboot. 
 However if it is a Cortex-M33 (trustzone) device like RA4M3, code in QSPI cannot run in secure mode as the entire qspi area is considered non-secure area, So application (in primary/secondary slot) will have to be a non-secure application. 
 The jump from MCUboot to application is not using R_BSP_NonSecureEnter(), so more work needs to be done. In short, Direct XIP only for internal flash. Another issue is difference in performance when running from QSPI vs internal flash. It is better to boot this image from internal code flash.