Problem: You have more than one monitor attached to the system, and the console is not set to an intended monitor.
If you have more than one monitor attached to the system, the OpenBoot firmware always assigns the console to the frame buffer specified by the output-device NVRAM parameter. The default value of output-device is screen, which is an alias for the first frame buffer that the firmware finds in the system.
A common way to change this default is to change output-device to the appropriate frame buffer:
ok nvalias myscreen /obio/cgfourteen ok setenv output-device myscreen ok reset
Another way of setting the console to a specific monitor is to change the sbus-probe-list NVRAM parameter.
ok show sbus-probe-list ( Display the current and default values) sbus-probe-list f0123 f0123 (Your system may have a different number of SBus slots) ok
If the frame buffer that you are choosing as the console is in slot 2, change sbus-probe-list to probe slot 2 first:
ok setenv sbus-probe-list 23f01 ok reset