X4200 M2 - How to redirect all display output to serial console

Hello, any advice on how to redirect all display output to serial console? machine SF X4200 M2

After poweron server, from serial console, I can only monitor SP bootup log and login to SP console. When I tried to run "start /SP/console" its just showing blank screen, no output display and no respon when pressing ENTER many times. I thought the server was hang, but actually it is not. When I access web GUI remote console redirection, the output display was there.

checked the eeprom output below:

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# eeprom

ata-dma-enabled=1

atapi-cd-dma-enabled=0

ttyb-rts-dtr-off=false

ttyb-ignore-cd=true

ttya-rts-dtr-off=false

ttya-ignore-cd=true

ttyb-mode=9600,8,n,1,-