topic Re: Low power boot M33 iMX93 in Zephyr Project

Low power boot M33 iMX93

CambridgeDev — Fri, 16 May 2025 16:32:57 GMT

Hi,

I'm trying to get Zephyr to boot on the M33 core on a phytec Nash iMX93 board. So far I have managed to:

Build hello-world from the MCUXpresso SDK
Used imx-mkimage to create a flash.bin for the iMX93 low power boot
Written flash.bin to an SD card using dd
Set the Nash board to low power boot from SD card mode

This worked (first time!) and I can see the hello world output on the UART2 VCOM.

I then built the Zephyr hello-world sample for phyboard_nash/mimx9352/m33, and followed the same steps as above to get a flash.bin on the SD card.

Unfortunately, this doesn't seem to work - I was expecting (hoping) to see the Zephyr boot messages on UART2, but no luck.

Can anyone help me with this ? The examples I've found all start Zephyr on the M33 from Linux on the A5s, which I don't want. We need to boot into Zephyr on the M33, and then start Linux from Zephyr.

TIA

Re: Low power boot M33 iMX93

JosephAtNXP — Mon, 19 May 2025 01:36:28 GMT

Hi,

Thank you for your interest in NXP Semiconductor products,

Please refer to the following link, zephyr needs to be booted over U-boot either from DDR or TCM.

Regards

Re: Low power boot M33 iMX93

CambridgeDev — Mon, 19 May 2025 07:57:20 GMT

Hi Joseph

Thanks for the response.

In general, Zephyr does not require a bootloader, and can be booted from bare metal.

In the link you posted it says:

To make a container image flash.bin with zephyr.bin for SD/eMMC programming and booting from BootROM. Refer to user manual of i.MX93 MCUX SDK release.

This is what we are trying to do.

Following the SDK guidance for creating a flash.bin container works for the hello_world SDK example; the M33 ROM boot code can load and run the program.

However, building a container image in the same way does not work for our zephyr.bin.

Please could you provide guidance on how to build a container with zephyr.bin that the M33 boot rom code an load and run. We don't have any security requirements at this point.

Thanks.