Problem with console while trying to upgrade to 6.1

[Marat N.Afanasyev]

I've encountered a problem while trying to upgrade from 5.4-p8 to 6.1.
My machine is placed in data-center, so I only have access to vnc-based
KVM to grab the console. With 5.4 I have no problem, but when I try to
boot 6.1 kernel it simply shows no information about loading process and
I have no way to single boot. It seems that something in vidconsole
prevents interaction with user at boot process. After entering
multi-user console again works fine. I have no idea what to do. Any
information concerning machine and KVM I use will be provided.

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SY, Marat