Where can I see errors when the kernel cannot be loaded?

Question

linux

Hello!
There is Malinka 3B (not +, if important).
I'm trying to roll a RealTime patch on the kernel 5.10.8, 64 bit.
The patch is applied without errors, the kernel (from the official Malinka repository) is compiled, but when you try to load a black screen ... That is, the Rasberry logo flashes with a rainbow square and then everything (the download does not go as usual, only occasionally blink the Act LED)
If you collect the kernel without a patch, then it boots normally.
Tell me, where and how can I see what exactly is wrong and what are the download errors?

Answer 1

I don’t know the solution, only the direction is to configure the console output to the serial port, attach the terminal to it and watch