Not able to boot after building kernel for BBG (using microSD)

Hello all,

My aim is to cross compile for BBG. I’ve successfully completed all the steps
that were needed to build the kernel and deploy it.

I have a microSD card with rootfs and BOOT partition.
rootfs has the kernel modules and BOOT has MLO, u-boot.img, uImage
and uEnv.txt.

After putting the SD card into the BBG and pressing the S2 button, LEDs don’t blink.
But when I press the Power button, LEDs start blinking but BBG doesn’t boot with that.

So my question here is that do I need to have an OS already flashed into the BBG and then
put the SD card which has the built kernel?

Or is it fine to have nothing into the BBG and then by just inserting the prepared SD card I can boot into it.

My second question - Is it necessary to have a USB to serial cable here?
I am not using a USB to serial cable here.


It's not "necessary"... It's just incredible useful to debug what's
actually going on..