Is it possible to boot (recovery, un-brick_) i.MX 8M Nano EVK with imx_usb_loader using UART4 ?

[jasonpowell_2]

I have i.MX 8M Nano EVK and trying to download u-boot image via UART4 (debug for A53)  to RAM and then run it. The board is in serial download mode. It appears that I can send the image using imx_usb_loader, but I am not getting any response from the board via UART4 (magic mismatch or just infinite loop trying to read). Is it possible to boot (recovery, un-brick) i.MX 8M Nano EVK with imx_usb_loader using UART4? If yes, could you please describe the steps? Can I use UART4 with uuu to boot? Or, another question: when the Nano EVK board is powered off and when using Putty (or Tera Term) to connect to UART, I can connect and send data, but I do not receive anything back from the board. Is there are a fix for this?

[jasonpowell_2]

Thanks, Aldo.

I am aware of USB OTG and I have used it successfully to download an BSP image with Linux using uuu. The system booted ok. However, I was trying to download u-boot.imx through UART using imx_usb_loader. Apparently I was able to send data but I was not getting any response from UART port. Interestingly, when I booted the system using eMMC, I was able to download image and get all expected responses from UART up to the JUMP instruction (but, of course, this was after the I booted system with eMMC). I was wondering when I am initially trying to download u-boot image why UART was not giving me any responses. BTW, even when board is not powered up, I can see UART ports as COM ports on my PC as expected. Or, another question: when the Nano EVK board is powered off and when using Putty (or Tera Term) to connect to UART, I can connect and send data, but I do not receive anything back from the board. Is there are a fix for this?

-JP

[AldoG]

Hello,

Unfortunately imx_usb_loader is not supported by us since it is not an NXP tool it may be a good idea to try on their github or forums.

Also, I'm not sure if you have the device in serial download mode when you first tried to load uboot trough uart.

Regards,
Aldo.

[AldoG · Accepted solution]

Hello,

It is possible to reflash uboot and/or linux/android, but you'll need to use the USB OTG port not the USB debug port.

Connect the board to J301 (USB Type-C Port1) through the USB Type-C to  your host PC, and try again.

Personally I don’t have much experience using imx_usb_loader, but UUU should do the job too, for the steps you may look here:
https://www.nxp.com/document/guide/i-mx-8m-nano-evk-board-getting-started-guide:GS-8MNANOLPD4-EVK

Hope this helps,
Regards,
Aldo.

[jasonpowell_2]

Thanks, Aldo.

I am aware of USB OTG and I have used it successfully to download an BSP image with Linux using uuu. The system booted ok. However, I was trying to download u-boot.imx through UART using imx_usb_loader. Apparently I was able to send data but I was not getting any response from UART port. Interestingly, when I booted the system using eMMC, I was able to download image through UART and get all expected responses from UART up to the JUMP instruction (but, of course, this was after the I booted system with eMMC). I was wondering when I am initially trying to download u-boot image why UART was not giving me any responses. BTW, even when board is not powered up, I can see UART ports as COM ports on my PC as expected.