i.MX ProcessorsのトピックRe: i.MX8 Generate a cold reboot to refresh bootloader .text/.data section

i.MX8 Generate a cold reboot to refresh bootloader .text/.data section

clementperon — Thu, 21 Jan 2021 09:29:37 GMT

Hi NXP Community,

We are looking to update the bootloader of i.MX8QM remotely on the field for board that's are always powered-on.

Unfortunately right now when you update the bootloader and then reboot from Linux the bootloader and SPL aren't reloaded:

When doing partition reboot, the boot image won't be reloaded by ROM,it is just CPU reset to boot entry. The SW has to keep the boot imageinside the RAM unchanged. It includes both the TEXT section and DATAsection.

As I said the board are always powered and can't be unplug/replug easily to generate a cold reboot.

Do you see any solution to generate a cold reboot from linux?

Thanks for your help,

Re: i.MX8 Generate a cold reboot to refresh bootloader .text/.data section

weidong_sun — Thu, 21 Jan 2021 10:45:49 GMT

Hi,

what I refer to is imx8qm-mek design files.

Linux reboot executes the PMIC_WDOG_IN network on the hardware, and PMIC_WDOG_IN is connected to the WDI pin of the PMIC. If you want cold reset, we must reset PMIC. Therefore, you can try it like this:
1. Connect R63 and R66 together with a wire
2. Connect R110 and R113 together with a wire
The purpose is to pull down the PWRON pin when WDOG sends a LOW level to reset the PMIC.

If this method fails to achieve your goal, it is difficult to find a better way.

Hope this information is helpful to you.

Have a nice day!

B.R,

weidong

Re: i.MX8 Generate a cold reboot to refresh bootloader .text/.data section

clementperon — Fri, 22 Jan 2021 11:03:20 GMT

Hi @weidong_sun,

This behavior was not observed with Linux 4.14 and appears in 5.4 release.

Also board are already shipped and can't be modify.

Regards,

Clement