This has been seen in two separate sites to my knowledge.
While setting up the OS on brand new T2000's, a laptop attached to the serial management port as console goes into its screensaver. When the laptop is brought out of the screensaver back to its active state (touch any key, move the pointer), the T2000 is at the ok prompt.
If the screensaver is disabled, the install process proceed to completion.
Has anyone ever determined if this is a bug or a feature? And other than saying, "Well, just disable the laptop's screensaver.", is this documented anywhere? Must everyone figure this out on their own?
It's a feature.
You're going to have to disable the screensaver.
You're seeing a classic symptom from various laptop systems.
When the screensaver kicks in, the rest of the system goes into a state comparable to a S1 level hibernation.
That halts most all other processes or applications that might be running.
The act of switching back, out of the screensaver, establishes the connections again.
Your Sun system is interpreting it as the same as an abrupt physical disconnect/re-connect of the cable.
Review the man pages for kbd_, although I don't think you can effect any usable changes while in the middle of the installation.