Character driver development

I am trying to learn kernel development by adding on character driver to print hello world. I am using fastboot method to flash updated kernel to dragon board but after a successful flash, I am unable to see any output on the screen. Does this mean during kernel flash process Debian OS also deleted from the board which was previously installed on the board?

Please anyone if you have any idea related to this helps me.

no, it means something wrong was done on your side, either when building the kernel, or preparing the boot image.

we have instructions to rebuild the release kernel in the release notes. Please try that first. you should be able to rebuild the kernel and the boot image using the released branch/version first.

if you’ve tried that and it failed, please provide detailed logs of what you’ve done, so that we can debug.