Kexec failing. How to debug further?

Hi, I am trying to use kexec to load new kernel but unable to load. How to debug furhter? I am working on a phone with platform x86_64. I have followed the standard steps those are mentioned in kdump.txt in linux documentation but the new kernel is not booting. I donot have serial port provision. Also, i followed the same steps on my Ubuntu PC and it works there. Any idea if we need to perform extra steps for x86_64 platform or in general for mobile devices? BR, Manty