Accessing U-Boot with an SSH Connection

Question

I need to access U-boot on a uPC that I have that is running Debian. Typically I connect my uPC to a monitor and during the boot up sequence press any key on my keyboard and I am immediately entered into U-Boot. However, it would make my life easier if I could access U-Boot when I am connected via SSH using Putty.

When you reboot, the uPC when connected via SSH you never see the boot-up screen and that is why I am not sure if it is possible to access it with this type of connection.

I only need to run two commands while I am in U-Boot setenv fdtfile imx7d-sbc-iot-imx7-can.dtb and then saveenv. If there is a way I can enter these commands while connected via an SSH connection it would be very helpful.

If anyone has any insight on how I could go about doing this it would be very helpful.

Thanks,

Mitchell

Answer 1

Obviously you cannot ssh to your iOT when in U-Boot since the Linux kernel has not yet even start booting.

One of the possible solutions is doing ssh to an wifi interface to another cheap iOT next to your board (for instance an Orange PI, or an rpi).

This second board has in their USB port the USB to TTL Debug Console Serial Cable, PL2303. This adapter is in turn connected to your target board in their JTAG/console pins.

Thus, you ssh to the 2nd board running Linux, and run a terminal program, for instance, minicom to connect via RS-232 to your target board.

Another possible solution is buying a bluetooth to serial adapter, and accessing it via bluetooth. I prefer the first one that answers directly to your question and it is often easier to get working and doing debug.