Enter serial bootloader while running

[carotte]

Hi,

Normally one would change the boot switches to change to serial boot instead of fuses, then precede to flash with UUU.

I would like to know if there is any way to make UUU trigger serial download mode on the device while it's running.

Thanks!

[carotte]

Hi Aldo,
Thanks for your reply!

The reason for asking was to see if the flashing could be done within an assembled device with no access to the boot config switches or the console. 

Since you mentioned uboot; is there perhaps a way to make uboot check automatically if a host computer is connected for serial download and if not precede with the normal boot ?

Thanks !

[AldoG]

Hello,

What I mean is that at uboot level you may run the command  I mentioned to go to serial download (USB boot).

Also, if ROM code already found a valid image and loads it, it won't start USB communication and continue the boot process, in the tool side (UUU) you'll see that it will keep waiting for a device to be connected.

Best regards,
Aldo.

[carotte]

Hi Aldo, 

I understood your suggestion, but my application requires a solution that works without console access on the embedded device.

Running a command in u-boot is therefore not an option.

[AldoG]

Hi,

You may run uboot commands without the need of the serial console, please remember that the tool perform uboot commands to flash.

In this same way you may boot into serial downloader (USB) by using the command I mentioned before by just adding it to a script, I have not tried before, but it should look like this:

FB: acmd bmode usb

Best regards,
Aldo.

[AldoG]

Hello,

It is rather odd, since to run UUU device should be in serial download to start working, there are some cases when the tool can communicate with the device when it enters fastboot as well, or is already at uboot.

Also, please do remember that it is uboot which should be able to do this not the tool (UUU), in this case for the i.MX6 & i.MX53 processors there is a command at uboot that may be usefull in this situation:

• bmode usb

This command will make the device go to serial downloader (USB boot).

You may find more information about this here:

https://source.codeaurora.org/external/imx/uboot-imx/tree/arch/arm/mach-imx/Kconfig?h=imx_v2020.04_5...

Best regards,
Aldo.