upgrading 5.4 -> 6.0 without reinstalling. safe ?

[Pertti Kosunen]

Ronald Klop wrote:
>>> 7. reboot into single-usermode and verify your new kernel works
 >>> 8. mount -a
> 
> How do you reboot into single-usermode from remote?
> (Rebooting isn't really the problem, working in single-usermode is.)

When i updated 5.4 to 6.0-BETA5 i skipped the reboot in single user and 
mount steps, system did get up normally with ssh after last reboot. 
Atacontrol usage changed and few ports needed reinstall (perl & modules) 
and system was ready.